Limestone caves are by far the most common type. Obviously they are mostly found in areas where the bedrock consists of a great shelf of limestone. However, dolomite and marble terrain can also serve as an environment for the creation of a limestone cave. A limestone cave is created by the erosive and corrosive action of water seeping through the rock. Rainwater in particular aids in the creation of a limestone cave, since the carbon dioxide absorbed from the air helps to make rainwater a dilute form of carbonic acid-a fluid that quickly eats away limestone. As the water seeps through the earth, gradually widening its passageways, the limestone cave grows. Shifts in the water table, caused by drought, floods, or gradual movement of terrain features, can increase or decrease the flow of water through the cave. If the water table drops, formerly underwater passages are left dry and full of air, creating a cave like those that have sheltered creatures since the beginning of time. Such caves can often be entered through the inlets or outlets of the water that once flowed through them. Although often tortuously narrow or steep, such openings are the most common
entrances to limestone caves. A cave that grows too large may not be able to support the expanse of rock above it, and the ceiling may collapse to form a sinkhole. Such a feature drops precipitously from the surface to the floor of the cave, but can be used as an entrance for characters willing to do a little rope work. When the water has drained from a limestone cave, it is not uncommon for seepage or even small streams to continue to trickle through it. It is the seeping of small trickles of water that creates many of the spectacular underground rock formations that are familiar to those who have ventured into caves. The most commonly known cave features are stony pillars known as stalactites (hanging from the ceiling) and stalagmites (growing upward from the floor). As with other cave features, they are created by the slow dripping of water, which evaporates and leaves behind small deposits of minerals. Depending on the types of minerals left behind, these cave features can range in colour from a muddy brown to red, or even (in rare cases) a pure crystalline white. Other types of cave features include draperies, flowstone, and
gypsum flowers. Draperies (also referred to as curtains) occur where evaporating water has left a sheet of stone that resembles a ruffled curtain. Flowstone often falls in a series of tiers and resembles flowing sludge. Gypsum flowers are rare and delicate little structures that can be extremely beautiful.

If a cave is subject to continuing water seepage, it is considered a living cave, and these features are slowly growing
throughout it. In fact, it is not unheard of for a cave’s features to grow so much that they literally fill in the cave that the same process (of dripping and running water) created in the first place. Features in a living cave glisten and shine when light is cast upon them. They are also very sturdy. Although occasional areas of rubble might obstruct passage, such caves are generally very clean and almost dust-free. Of course, this is before the cave is entered or used by creatures from the outside world or exposed to air from the surface. Mud is also a very common feature of a living cave. All low areas that are not regularly swept by flowing water contain pools of sticky mud. Depending on the drainage and shape of the area, these mud pools can be quite deep. A dead cave, on the other hand, is one in which the water no longer flows. The features in a dead cave do not glisten, and in fact grow very weak without the constant humidity to reinforce them. Left without water long enough, a cave’s features become very brittle and eventually crumble into dust. A dead cave is much more likely to be choked with rubble than its living counterpart. A layer of dust often covers everything. If water can be found, it has generally been standing in a pool for centuries. Even so, the water found in such locations is very rarely stagnant-the cold temperatures and lack of sunlight see
to that. Some limestone caves are completely filled with water. These caves do not have the features described above, unless those features were created when the cave was filled with air, and it has subsequently filled with water. In general, the passages in a water-filled cave are smooth and rubble-free. Nonetheless, the water may flow through very narrow openings or tightly winding passages, making it difficult or impossible for a character to travel
through.

Sea caves are formed along current or former coastlines where the erosive action of pounding surf gradually wears an entrance into the bedrock. They are generally much smaller than limestone caves, since the waves disperse their energy quickly as they work their way inward. Sea caves are often partially water-filled. Depending on the changing level of the water, a sea cave might even be completely submerged, its mouth hidden to all observers who are not themselves submerged. On the other hand, if the water level has fallen or the ground has risen, a sea cave might be discovered in a cliff far above the pounding surf, or even many kilometres inland if the coast has gradually moved farther out to sea. Sea caves have smooth floors, walls, and ceilings, with none of the spectacular features of their limestone cousins. On the other hand, their often relatively easy access makes them more likely to contain some relic of long-past inhabitants. When a river flows around a bend, the abrasion of water against the outer riverbank might erode a space that eventually becomes fairly large. Such caverns resemble sea caves in most respects.

Mines in a fantasy world are almost always tunnels or shafts. Some mines, particularly those developed over many centuries by diligent excavators such as dwarves or gnomes, can become complicated networks of tunnels extending through three dimensions and stretching for dozens of kilometres. Mines can be either active or inactive, which indicates whether or not they are currently in use. The miners who created an inactive mine might have ceased their work because the vein of material they were excavating was depleted, but this is not necessarily so. Disasters or conflicts might have forced the operation to discontinue. Active mines are usually well-guarded, and inactive mines often become the lairs of subterranean monsters.

Burrows are generally long tunnels, perhaps with a widened spot at some point, created by creatures as shelters. Only very large burrows are big enough for characters to enter; unfortunately, very large burrows are usually created by very large creatures that do not always react kindly to the intrusion. Burrows are generally excavated from dirt, but certain creatures (such as umber hulks) can create burrows in solid stone. A burrow is generally no bigger in diametre than the creature who created it, although a larger chamber is often excavated at the burrow’s deepest end.

Standing water gathers wherever the flow of water into an area becomes so dispersed that a current is no longer readily detectable. Although water may still flow through an underground lake, the current travels so deeply or slowly that it cannot be observed. The characteristics of underground lakes and seas are very different from their counterparts on the surface. The absence of wind is a significant difference, but the overhanging ceilings make an even more pronounced impression. If the ceiling over an underground lake, pool, or sea is so low that it touches the surface of the water or leaves only a few inches of clearance, normal boat travel is impossible. The absence of wind means that sailing is virtually unheard-of underground, except in those rare instances where the ventilation is ample enough to create a wind capable of moving a boat. Waves are practically nonexistent. Thus, underground lake and
sea shores are not eroded by wave action, although magical forces or falling objects can cause occasional waves. A cave-in somewhere above or next to a lake often forces a powerful wave outward, much like a tsunami on the surface. In fact, the earthquakes that cause tsunamis in the outside world often produce similarly destructive waves in the Underground. The action of such waves is often amplified and confused by the confining walls that enclose most underground bodies of water. If a large wave starts in a small underground body of water, a deadly and chaotic surface of choppy waves can last for many turns. The exact duration of such disturbances is left to the GM’s discretion, since it depends on the force that created the original wave and the size of the area enclosing it. Other causes of waves include animal, monster, and humanoid activity, and streams flowing into a standing body of water. Characters confronted with waves on an otherwise still body of subterranean water are wise to determine the source of the disturbance.

Lakes and pools make up the majority of underground bodies of water. They differ in size (lakes are larger), but both contain fresh water. Large pools and lakes often support a wide variety of living creatures. Even small pools may hold such creatures, as long as a sufficient food supply is available in the water, or (in the case of amphibians) in the surrounding area. Lakes and pools can be found at nearly all depths of the Underground, from a few hundred metres below the surface to the farthest depths of the world. If a lake or pool has a stream or spring flowing into it, the water is almost always safe to drink.

Reservoirs are commonly created by the intelligent denizens of the Underground. As might be expected, each reservoir is contained by a dam of some kind-but this dam is not always built along the side of the reservoir. It may, in fact, be located at the reservoir’s bottom, and serve much the same function as a cork in the bottom of a leaky bucket.
Occasionally a reservoir is formed as a secondary result of some race’s attempt to regulate the flow of water for irrigation, transportation, or defence. In any event, reservoirs have most of the same characteristics as underground lakes and pools.

Seas lie in the deepest depths of the Underground. As on the surface, seas contain salty water heavy with minerals that have been dissolved from the surrounding rock. Because of their age, seas are almost always huge in comparison to other underground bodies of water. Whole races of intelligent and unintelligent creatures inhabit the seas of the Underground. Some of these seas are cold, vast, and deep. Others lie so close to geothermal heat sources that their waters are warm and the air surrounding them is heavy with steam. These seas are so far away from the surface of the world that they are rarely seen by outsiders. Even if a navigable path is somehow found through a long network of underground streams and rivers, a return trip of such a distance without the benefit of a current is almost unthinkable.

Flowing water is more commonly encountered underground than standing water. Indeed, it is flowing water that has shaped much of the underground environment. The characteristics of a flowing body of water are determined by three significant measurements: the diameter of the waterway, the percentage of the passage that is filled with water, and the rate of flow. The following four categories describe the various types of passages through which underground waterways flow. Impassable waterways are too narrow for a fully equipped party of PCs to move through. These passages may be as narrow as a few inches-small cracks that spew forth considerable volumes of water-or they may be wide enough for characters to wriggle through. At least part of an impassable waterway must be less than three metres in diameter. Narrow waterways include streams and rivulets. A narrow waterway follows a path less than 6 metres wide, and is generally less than 90cms deep. Average waterways include streams and small rivers from 6
to 18 metres wide. Although occasionally shallow enough to wade in, average waterways are usually 1 to 3 metres deep. Wide waterways include all areas of flowing. water more than 18 metres wide. The depth of such a waterway is generally greater than 3 metres, at least in the centre. The water near each bank is often considerably shallower.
Occasionally an artificially constructed underground waterway may be encountered. These include canals, which allow water transportation between areas, and aqueducts, which move water from one location to another. The underground races also use flowing water to turn water wheels, creating a power source for fans, pumps, and other machinery. In some locations, water powered pumps are even used to operate locks on underground canals.

The rate at which water flows through an underground stream determines a number of other characteristics of the waterway: how quickly the riverbed erodes; how quickly the river loses altitude in its travels (remember, all rivers flow downhill to some extent); how much noise the river makes; and how dangerous the river is to travel upon. The maxim “still waters run deep” is more than an idle phrase. The deeper a given body of water, the more slowly it runs. Thus,
areas of savage and churning rapids tend to be rather shallow; the same amount of water moves much more gently along a deep riverbed.

Stagnant water seems to have no flow whatsoever. Stagnant water is encountered in a stream or riverbed when
there is no downhill flow. Instead, the water collects in pools and low spots in the riverbed. While travel along a stagnant body of , water is not threatened by flow, it may be difficult if the water is too shallow to support a boat.

Placid water usually has a noticeable flow. It is sometimes necessary to drop bits of wood, dust, or other floating
objects into the water to determine the direction of its flow. Placid water is often encountered near the mouths of streams or rivers or in lakes. A placid waterway has a barely perceptible drop in altitude as it flows along, often no more than 3 or 4 metres per kilometre. Any rocks or other obstacles in the water can be easily avoided. The rate of
flow of such a stream is 12 metres or less per round.

Medium flowing water is the most pleasant for travelling downstream. The water flows along at between 12 and 36 metres per round, descending only slightly on its course. A river with a medium flow may drop as much as 9 metres over the course of a kilometre. Travel along this type of waterway is relatively safe, but characters must keep a lookout for potential obstacles such as rocks protruding from the water. With care, obstacles are easily avoided, but characters not paying attention may be drawn into an unfortunate collision by the force of a medium flow of water. A river with medium flow has few if any sudden drop-offs. When PCs travel along such a river, the GM should roll D6 for each kilometre travelled. On a 5 or 6, a drop-off of D3 metres is encountered somewhere in that kilometre.

Rapid flowing water is more commonly called rapids. The water spills and rolls along with a muted roar, crashing into and around any obstacles in its path. Water flowing through rapids travels more than 36 metres per round-sometimes as much as 52 metres per round. The descent of the stream bed ranges from 9 metres to as much as 60 metres over the course of a kilometre. The sound of rapids can be heard by characters and creatures within 300 metres. Travelling upstream along rapids is impossible unless powerful magic is employed. Travelling downstream along rapids is dangerous, but possible. Certain kinds of boats, such as kayaks, are more suited to rapids than most standard boats. Characters who try to boat down a rapid stream without possessing boating proficiency will find themselves in great danger. Rapids generally have many sudden drop-offs during the course of their flow. For each kilometre that the PCs travel along a rapid stream, the GM should roll D6. A result of 6 means that no significant drop-offs occur during the kilometre. A result of 1-5 is the number of drop-offs encountered. Each drop-off falls D4 metres.

Cascades are steeply dropping portions of a river where the water tumbles from one level to the next in a foaming series of short drops. A cascade is much like a stairway with water running down it. The thundering roar of a cascade is usually audible at least a kilometre away from the river. Water spilling down a cascade travels at anywhere from 72 to 180 metres per round. The waterway descends at a slope of at least 60 metres, and perhaps as much as 300 metres, in a kilometre. Travelling upstream against the force of a cascade is impossible; travelling downstream might be possible for a lucky character with boating proficiency who is in a kayak. A cascade, by its very nature, includes many drop-offs. If PCs chance to travel down a cascade, the GM should roll 3D6 for each kilometre travelled. The result is the number of drop-offs encountered during the course of that kilometre. Each drop-off is D6 metres high.

Waterfalls represent flowing water at its fastest and most powerful. A waterfall is created wherever flowing water falls freely to a lower level instead of flowing along a bed. A long stretch of waterfalls, with rapids or cascades between them, is still considered a waterfall. The speed of water plummeting over a fall is at least 180 metres per round. The exact speed depends on the number of steps in the fall. While it is theoretically possible for a waterfall to plunge thousands of metres straight down, most waterfalls include areas where water flows forward along a bed. For purposes of this rule, anywhere the water plunges at a slope of more than 300 metres per kilometre is considered a waterfall. The nature of a waterfall makes it impossible to control a boat travelling over the fall. Although characters in boats might survive a plunge over a waterfall, such survival is more a matter of luck than skill.

Underground waterways are as susceptible to damming as their surface counterparts. Because of their confining environment, damming underground rivers or streams often produces dramatic results. The success of a damming attempt by PCs must be adjudicated by the GM. Is sufficient material available to fill the passage to a suitable height? Is the water flowing so fast that any damming material will be swept away? If an underground waterway is dammed, it immediately begins to back up and flood behind the dam. A GM confronted with this situation must rely on accurate three-dimensional maps. The water may well be diverted into other parts of an underground setting, filling rooms and making its way through corridors and down stairways. As soon as the water level reaches a height that allows it to flow through another channel, it changes course to follow the path of least resistance.

Unless some external source of heat is contributing to the water temperature, underground water is almost universally cold. Although water rarely freezes underground, its temperature is numbing to any characters who get soaked in it.
Some underground water flows directly from above-ground sources such as shallow seas, lakes, and meandering rivers. If the water is relatively warm when it leaves its source, it retains this warmth for D4 kilometres. Underground water can also occasionally be warmed by geothermal heat sources-the same sort of heat energy that gives rise to geysers and volcanoes. Depending on its proximity to the heat source, such water might be only slightly warmer than the usual underground waterway, or it might be so hot that a character falling into it is scalded to death very quickly.
Characters immersed in water that is at or near boiling temperature suffer 6D6 of burn damage per round spent in the water. No saving throw is allowed, although characters with any kind of magical protection against heat or fire gain a -2 per die of damage (minimum of 1 point per die). Characters only partially immersed in such water only suffer
partial damage. The GM must establish a proportional number of D6 of damage based on what proportion of the characters’ bodies is exposed to the water. Water that is very hot, but not near boiling temperature, inflicts D6 points of damage to characters immersed in it. Characters who are only partially exposed, or who have any kind of magical
protection against fire and heat attacks, are not affected. If the water is no warmer than very hot bath water, characters suffer no ill effects from the heat.

Many dungeons are prone to being both cold, because they are shielded from the sun's rays, and damp, because they have vast quantities of water in them. Although this condition may not immediately become an obvious threat to the lives of the characters, it can make them quite uncomfortable and, if left uncountered, can prove fatal. Attempts to counter the cold, by warming oneself before a camp fire or the like are all well and good, but have the disadvantages of aerating a light (thus announcing your firkin presence to everything in the area) and using oxygen to feed the fire (thus making your own breathing supply more limited). The players will have to weigh the risks and benefits of this course on their own.

Water is almost always dangerously cold in the Underground, since it is never warmed by sunlight. A character who becomes soaked in cold water is much more vulnerable to cold conditions than a dry character. Moderate temperatures are treated as cold temperatures for the purpose of determining whether the soaked character suffers cold damage. This vulnerability remains for 2D4 hours or until the character changes into dry clothes; soaked clothing provides no protection. A character who remains immersed in cold water for more than 1 minute takes D6 points of nonlethal damage per additional minute of immersion.

On the other end of the spectrum, there are subterranean realms in which cold air and water are not likely to become problems. One seldom catches a chill, for example, from attempting to wade through a pool of water which has been heated to near boiling temperatures by geothermal activity. On the other hand, anyone in such a situation is certain to be badly burned. Geothermal heat is found in many forms. Most commonly it manifests itself in hot springs and
geysers of steam. In more exotic locales, it may be found in the form of a stream of molten lava or a boiling lake of magma. In the latter case, the air is apt to be thick with brimstone, a noxious (or even toxic) vapour. Caverns heated by geothermal activity can be quite warm; in fact, hot or severe temperatures are common near volcanoes. Any chamber with exposed magma is severely hot, and possibly extremely hot (see Heat Dangers).

Suspension bridges are among the easiest to build. They are generally anchored in at least two locations on each side, and often in three or four. Suspension bridges swing and sway with the weight of a character’s crossing, but usually a rope or two is provided at waist level for handholds. The problems with suspension bridges generally relate to the rotting of the wood and rope elements of the bridge, although occasional loosening of the anchors can also present problems. An old suspension bridge has a 25% chance per character crossing it of giving way at some crucial point. If this occurs, the character must make a successful Climbing Check or fall. If the character fails the first Climbing Check, this means that he has fallen through the bridge or off to one side. He is entitled to one more Climbing Check to determine if he can catch a piece of the bridge and arrest his fall. If the character has only one hand free, this check is made with a -25% modifier. The character can drop whatever he is holding in order to free both hands. Sabotaging an anchor point of a suspension bridge takes D8 rounds, and such sabotage can only be detected by a find traps roll. Sawing through a rope support of a suspension bridge can be done in one round, but such damage is readily visible to any character who examines the bridge.

Wooden bridges are relatively uncommon in dungeons, since the constant humidity makes them very susceptible to rot. Unless a bridge has been inspected and repaired at least once in the past year, it stands a 5% chance (per year) of sustaining rot. Rot will first affect the planks and railings of a wooden bridge; the actual supporting beams of the bridge last for D20+20 years before beginning to rot. If characters attempt to cross a rotted bridge, each character
stands a 50% chance of stepping onto a rotten portion. If this occurs, the character must make Climbing Checks to determine whether or not he falls, as described for suspension bridges.

Stone bridges are the most solid of all. They are virtually impervious to the effects of sabotage and age. Of course, occurrences such as earthquakes and floods can weaken stone bridges, but even when weakened, a stone bridge will rarely collapse because of the added weight of a character. However, stone bridges depend upon some kind of support in order to maintain their massive weight. This support might be an arch attached at both ends of the bridge. A stone bridge may also be supported by foundations, each of which is crucial to the bridge’s survival. In these cases, magical sabotage-particularly the transmute rock to mud spell can cause drastic damage to a stone bridge. If the centre of an arch is destroyed, the entire bridge will collapse in D4 rounds. If a foundation is destroyed, the bridge will instantly collapse in both directions from the ruined foundation until it reaches the next foundation, or the end of the bridge.

Rope bridges require two ropes, one for a character’s feet and one for his hands. A character crossing a rope bridge must make a Climbing Check with a +50% modifier. Note, however, that modifiers for armour affect this roll normally.
Rope bridges can be quickly sabotaged by chopping through one of the ropes. A character on the bridge when this occurs must make an unmodified Climbing Check or fall. If the character is clinging to the sabotaged rope with his hands, the check must be made with a -2 modifier; alternately, the character can elect to hold onto the rope and swing down with it.

Cave-ins are a constant problem to creatures living underneath tons of earth and rock. Cave-ins can be triggered by erosion, or by sudden shocks such as earthquakes or explosions. Of course, characters or creatures directly underneath a section of dungeon or cave that caves in suffer damage from the material falling on them, and are often pinned by the weight of this material, or trapped in a small area with little air. Dungeons are often protected against cave-ins by shoring up the passages with timbers or stone arches. Caverns do not have the benefit of such engineered protection, and realms are generally too vast for such protection to be practical. Because of their vast size and durability, the realms of the underground are rarely subject to cave-ins. If a cave-in occurs in a realm, however, its
potential for disaster rivals that of the worst hurricane or tidal wave ever to ravage a surface land. Although not a common occurrence, the chance that the roof of an underground location may cave in is something that must be
considered, especially if characters are excavating, using explosive magic, or otherwise placing stress on the overhanging rock. Although the usual effect of a cave-in is to bring the roof of an area crashing down upon its inhabitants, cave-ins can also endanger characters in other ways. Characters may even try to trigger a cave-in as a
means of attacking an enemy; such attempts must be made cautiously, however, since a cave-in may create a chain reaction that collapses a far larger area than intended.

Most underground settings are solid enough not to collapse unless subject to a great deal of external pressure. In general, a strong cavern, dungeon, or realm is only susceptible to cave-ins as a result of natural disasters such as floods, earthquakes, or volcanic eruptions. Certain magical spells that duplicate these natural disasters can duplicate their destructive effects as well. A raise water spell that creates a flood in a tunnel, for example, should be treated as a natural flood. In the case of a major natural disaster, the GM’s judgment must be used to determine the exact area of effect. Occasionally underground areas are ripe for cave-ins. Perhaps aging has caused much of the supporting rock in an area to crack and crumble, leaving only a thin area of solid support-or maybe a recent earthquake or flood has left an area so weakened that only a slight additional bit of pressure is required for the entire area to fall inward. Such areas should be noted when the maps for an underground area are prepared. Only the frailest of underground locations are susceptible to accidental cave-ins. These collapses are triggered by the weight of a creature walking across a weak spot, or even by the sounds created by characters or creatures. Based on the weakness of the area under consideration, the GM should assign a percentage chance of a collapse occurring. If the characters participate in melee combat on such a fragile surface, not only must the weight of all participating creatures be figured in (figuring carefully the weight of nonhuman creatures such as ogres), but the chance of a collapse should be doubled because of the additional pounding that the surface takes. In cases where the weakened area is not directly beneath the characters, the chance of a cave-in is reduced. Unless the characters apply weight to the area, sound is the only other likely avenue for causing an accidental collapse. An area that could be triggered into a collapse by sound waves is very fragile indeed. The intensity of the sound must be considered, with a percentage chance of collapse assigned according to the loudness and sharpness of the noise. For example, an area might stand no chance of collapsing under the sound pressure of normal conversation, but the clashing of swords in combat might give a 1% chance per round of a cave-in.

Whenever characters or creatures are digging into the earth, they run the risk of excavating away a significant support for the ceiling, causing a cave-in. Mining is the most common cause of this type of cave-in, and precautions such as shoring up an excavated passage are usually taken by the miners. More details on these procedures are provided later in the rules for mining. Characters trying to dig an escape tunnel or clear rubble from a previous cave-in are often unable to properly shore up their excavated passage. In this case, weakened surfaces stand a fair chance of collapsing. Generally, the possibility of a cave-in under such circumstances is about double that of an accidental cave-in. There is about a 10% chance per turn that a weakened ceiling or tunnel wall collapses during excavation. It is not unusual for characters or underground denizens to intentionally weaken an area so that it caves in at an opportune
time-at least, opportune in the minds of the saboteurs. As with all types of cave-ins, the success of an attempt to purposely weaken a structure or surface depends on the inherent strength of the area. Many areas subject to such sabotage collapse on the heads of the saboteurs themselves. Columns that support a ceiling, bridge supports, or narrow layers of rock over which characters or creatures walk are obvious targets for sabotage. To chip stone away to the point where a collapse is likely requires some skill at stonework and a little luck. A character must have miner proficiency to have a decent chance of successfully sabotaging an underground area. A character without miner proficiency who makes a sabotage attempt should have a +3 chance of successfully completing his task. Of course, an area-or at least the stone that supports an area-must be reached in order to sabotage it. The soaring ceiling of a vast underground chamber is very difficult for a character to damage. The columns that support that ceiling are much more
accessible. These attempts take considerable time and create quite a bit of noise.

If a campaign focuses on the underground for extended periods of time, the chance of a naturally occurring cave-in affecting the characters increases. Even though the chance is not very great at any given moment, if characters spend enough time underground they are certain to eventually encounter some sort of cave-in. The base chance for a cave-in during the course of the characters’ underground exploration is 1% per day. On long expeditions, the GM may wish to alter this roll to a 10% chance rolled every 10 days. If the roll is successful, this means that a cave-in has occurred
somewhere in the underground region near the PCs. This does not mean that the cave-in occurs on top of the characters, or even within their earshot. It is quite possible for a group of characters to fail to discover a cave-in that occurs during their adventures. In areas of exceptionally decayed stone, or of rotten supporting timbers, the GM may increase the chance of a randomly occurring cave-in. Such considerations could double, or perhaps triple, the chance of a cave-in.

A significant menace is created when even a small section of an underground location caves in, even if the cave-in does no immediate harm. The force of gravity is constantly attempting to work its destruction on the ceilings of the underworld; even a small cave-in can so weaken supporting structures that a massive chain reaction of collapse begins immediately, or threatens an area in the near future. When a cave-in occurs, the areas of nearby ceilings and walls must be checked to see if they weaken or collapse as a result of the original cave-in. Areas that collapse as a result of a chain reaction force checks for chain reaction collapses in all adjacent areas. The percentage chance for such a tertiary collapse is half (rounded up) the chance for the original chain reaction cave-in, If the chain reaction
continues, each subsequent roll is made with 1/2 the chance of the chain reaction roll that forced it. If an area is exceptionally weak and decayed, however, the GM may ignore the declining chance of a chain reaction cave-in and
use the original cave-in chance for all subsequent rolls. This is common in areas that have been heavily eroded by water or other natural forces, or in areas that were constructed long ago and left to fall into a state of ruin.

A flaming torch consumes all of the oxygen in the same space in eight hours. Of course, when all of the oxygen is consumed, the fire goes out. The oxygen consumption of larger fires is based on the number of small fires they equal. A fire four times larger than a small fire consumes oxygen four times as fast. A flask of burning oil does not burn for very long, but uses up a lot of oxygen while it burns. In general, oil in a flask or similar small container burns for three rounds. For purposes of oxygen consumption, however, treat the burning oil as a small fire (as explained above) and treat each round of burning as a full turn. Thus, an oil fire that lasts three rounds uses up as much oxygen as a small wood fire burning for three turns.

The smoke that accompanies fires causes additional problems. While fire consumes the oxygen that characters need to breathe, smoke acts as a poisonous gas that fills enclosed areas and is unavoidably inhaled along with any remaining oxygen. While it is possible to burn extremely dry and flammable materials with little or no smoke, most fires are not this efficient. If any of the fuel for the fire is wet, or if green or living branches, twigs, or leaves are used, smoke is produced. Any kind of burning fabric creates smoke, as does burning oil. The average amount of smoke produced by a small fire in one turn is enough to create a one-foot-thick smoke layer in a 3 metre x 3 metre square area. The smoke rises to the highest part of a room and collects in a layer against the ceiling. The next turn’s worth of smoke collects immediately below the first layer, and so on, until the breathable air is concentrated in the few metres nearest the floor. Finally the entire room fills with smoke and even characters lying on the floor are affected. An oil fire creates the same amount of smoke as an average fire, except that in an oil fire the rate is calculated by round instead of by turn. The smoke rate of a larger fire is calculated just as the oxygen consumption, so a fire that is three times as big as a one-foot-diameter fire creates smoke three times as fast. A character forced to breathe smoke must make a Constitution Check each round that the smoke is inhaled. A failed check means that he suffers D6 hit points of smoke damage. Smoke damage is temporary. If a character has a chance to breathe fresh air, the smoke damage goes away at the same rate that it was acquired-Le., the character makes a Constitution Check every round of breathing fresh air, with success meaning that he has regained ld6 points. Although temporary, smoke damage is real in the sense that any other damage taken while a character suffers from smoke damage must be considered cumulative with it.

Irritating fumes cause coughing, stinging of the eyes, dizziness, and similar difficulties. A character exposed to irritating fumes must succeed on a CON save once per minute or become sickened. Recovery from this condition is not possible until the character leaves the affected area. While not actually deadly, fumes can be quite overpowering and make breathing difficult and distasteful to adventurers. Dungeon masters can introduce noxious vapours from a wide variety of sources. Rotting garbage, for example, can produce a stench which is so overpowering to the average human as to induce gagging or even vomiting. A modern example of noxious vapours would be tear gas.

Poison gases are deadly. Anyone who ventures into an area of poison gas must succeed on a CON save once per minute or take D4 points of Constitution damage. Some poisonous gases also have the characteristics of irritating fumes, so their presence is obvious. Others, however, offer no telltale burning of the throat or stinging in the eyes to warn creatures of the danger. Any creature exposed to poison gas is entitled to a smell check to detect the threat before breathing enough to force a saving throw. With a successful check, the creature can retreat before risking any damage. A creature with the scent ability gains a +5 bonus on this check. These gases can be of natural origin, such as the sulphur dioxide commonly created around areas of volcanic activity, or can be of magical or manufactured origin. Obviously, the use of poison gas as a weapon of war is greatly enhanced in the constricted conditions of the underground. In many cases, toxic gases will carry a distinct odour which may allow characters to detect them before they reach dangerous concentrations. In other instances, however, they may be utterly odourless and colourless. In the latter case, the party may be overcome by the fumes before they are able to react to them. Of course, the most common means of detecting odourless toxic gases is with the aid of a small songbird in a cage. As these fragile
creatures are far more sensitive to toxic gases than humans or demihumans, they can act as early warning devices. In short, if the bird dies, get out of the area quickly.

Some naturally occurring gases can explode in the presence of open flames. If a burning torch or lit lantern is brought into a pocket of explosive gas, the vapour explodes, dealing 3D6 points of damage to each creature in a 3 metre radius. An alert spelunker might notice the danger before causing an explosion, since the open flame often behaves strangely (burning in a different colour or exceptionally brightly) right before the explosion. Allow the creature carrying the light an WIS check to observe the danger before the explosion actually occurs. If an open flame remains in the hazardous area thereafter, there is a 50% chance of an explosion in each subsequent round. Explosive gases can lurk undetected until a party of adventurers wanders in with an open flame. Once ignited, they release vast amounts of heat, light, and energy in a sudden violent chemical reaction—that is, they explode. To make matters worse, many explosive gases are toxic or noxious, compounding the danger of encountering them. In regions where coal or oil is common, explorers are prone to encounter pockets of methane (natural gas) which is toxic, explosive, odourless, and colourless. A more lethal combination would be hard to imagine.

Gases can originate from a number of underground sources. Volcanic activity can create deadly emissions of sulphuric gas that are every bit as poisonous as the bite of a venomous creature, while garbage or sewage can generate noxious gases such as methane whose smells are so overpowering that characters have a difficult time breathing them. The occurrence of such gases is primarily a campaign function to be handled by a GM at the appropriate time.
Certain types of gases, such as natural gas, are either odourless or possess such a mild door that the characters may not be aware that the gas is present until they start making checks or saving throws. Other types of gases, such as sulphur, carry such a strong odour that the characters might have a chance to hold their breath before the full force of the gas can take effect. Natural gas, often encountered in regions where coal and oil are common, has the additional hazard of being explosive. Any gas, whether poisonous, noxious, or harmless, can cause problems to characters by replacing the oxygen in a given area. In this case, the effects should be treated as if part or all of the ‘oxygen in a location has been used up, as explained earlier.

Certain creatures, most notably small birds, are more sensitive to poisonous gases than humans and other character races are. If, perchance, a party has a small bird with them and becomes exposed to a gradually increasing amount of poisonous gas (not including noxious gases), the GM should make a secret saving throw vs. poison for the bird one turn before the characters must save. The bird saves as a O level human, and if the saving throw fails, the bird dies.
Note that this procedure is of little help if gas is suddenly introduced to an area in high concentration. The party must
encounter a gradually increasing amount of gas in order for a bird to provide any early warning.

Assuming no ventilation whatsoever, a human-sized creature at complete rest depletes the oxygen in 3 cubic metres of air within 24 hours. If the creature performs even moderate physical activity, the duration of air supply is reduced to 12 hours. If the creature spends its time in any kind of strenuous exertion, the duration of the air supply is reduced to a mere six hours. If a character spends some time engaged in heavy or light exertion and rests at other times, simply calculate the oxygen consumption in multiples of the resting rate. Thus, a character who is working strenuously uses oxygen four times faster than a resting character, and a moderately exercising character uses the oxygen up twice as fast as a character at rest. A character who rests for three hours and then works hard for five hours has
used up as much oxygen as he would in 23 hours (3 hours + 4 x 5 hours) of rest. A GM can apply this ratio to all characters and to any creatures, such as mules or dogs, that accompany them. An accurate duration figure can be achieved by figuring the weight of the creature into human equivalents. A character does not instantly die when his air supply has been used up, but serious problems arise. Each turn following the exhaustion of the oxygen, the character must make a Constitution Check. Every time the check fails, each of his ability scores and his hit point total are reduced by one. Each additional Constitution Check is made against the reduced Constitution score. Thus, a character grows more and more feeble as he gulps the last remnants of the oxygen supply. When all of a character’s ability scores have dropped to 0, he is unconscious. When a character’s hit point total reaches the negative version of his total, he is dead. Even for a character with a large number of hit points, this fate becomes automatic once the Constitution score reaches 0, since all further Constitution Checks automatically fail. This system is used only for characters in an area with air; it cannot be used for characters who are holding their breath. If fresh air is introduced to a character before death occurs, he begins to recover immediately. Hit points and ability scores all climb at the rate of three points per turn until the character reaches his original levels in all areas.

In general, the Underground is surprisingly well ventilated. Vast subterranean spaces and the rare planar connection to the Elemental Plane of Air provide plenty of good air for living creatures. However, this is not universally true.
Sealed chambers, isolated caves, and water-isolated caverns have finite supplies of good air. Creatures that don't breathe need not concern themselves with air quality, but other travellers do. Any enclosed space that is reasonably airtight can quickly become stale or depleted. In general, a Medium creature depletes about 300 cubic metres of air (a 10-foot cube) every 6 hours. A Small creature requires one-half as much air, and a Large creature four times as much. Air becomes stale when it is halfway to depletion. Regions that are poorly ventilated are not immediately deadly, but the stale air can quickly wear out even the hardiest travellers. A character in stale air must succeed on a CON save each hour or become fatigued. A fatigued character must succeed on a CON save each hour or become exhausted. An exhausted character takes D6 points of nonlethal damage every 15 minutes until the condition is corrected. Characters cannot recover from their fatigue or exhaustion until they reach an area of good air. Depleted areas can prove deadly in a matter of minutes.

Ventilation of an underground area depends on several factors. Chief among these is fresh air flowing into and through the area. Any underground chamber with a noticeable airflow is considered well-ventilated. Smoke does not accumulate in such an area, nor is the oxygen exhausted by characters breathing or by fire. The duration of all gas based spells is halved in such an area. Poisonous or noxious gases remain in a ventilated area for two turns unless more of the gas is introduced. More subtle air movement can be detected by the flickering of a torch or candle. Even when characters cannot discern this movement through their own sense of touch, fresh air for breathing is not a problem in these areas. Gas-based spells linger for their normal durations, and poisonous or noxious gases remain
effective for one hour. Smoke from small fires or torches does not accumulate in moderately ventilated areas. Some areas appear to contain no ventilation, but are actually connected either to ventilated areas or to the earth’s surface. Characters do not use up all of the air through breathing; even this minimal amount of ventilation allows enough air movement for respiration. Poisonous or noxious gases remain in such an area for D4+1 hours. The duration of all gas based spells is normal. An area that contains no noticeable ventilation and has no place for smoke to flow out horizontally or upward captures smoke at the normal rate (even from small fires). Poisonous or noxious gases, unless specifically noted as being heavier than air, remain in such an area for a full 24 hours. Areas that are completely sealed off from any outside passages, either through cave-ins, constructed barriers such as mortared stone walls, or magical barriers such as walls of force, are subject to all of the effects listed, at their normal rates of accumulation
and effect. The air supply is finite, and once used up, cannot be replaced except through the introduction of fresh air.
Smoke that collects in such a room lingers for D6 hours after the fire that created it goes out. Poisonous or noxious gases remain in the area until vented out by the admission of fresh air. Again, the duration of all gas-based spells is normal.

With a successful Climb check, you can advance up, down, or across a slope, a wall, or some other steep incline (or even a ceiling with handholds) at one-quarter your normal speed (MR). A slope is considered to be any incline at an angle measuring less than 60 degrees; a wall is any incline at an angle measuring 60 degrees or more. A Climb check that fails by 4 or less means that you make no progress, and one that fails by 5 or more means that you fall from whatever height you have already attained. You need both hands free to climb, but you may cling to a wall with one hand while you cast a spell or take some other action that requires only one hand. While climbing, you can’t move to avoid a blow, so you lose your Dexterity bonus to AC (if any). You also can’t use a shield while climbing. Any time you take damage while climbing, make a Climb check. Failure means you fall from your current height and sustain the appropriate falling damage. 

Walls that are very smooth, smooth with cracks, or rough can only be climbed by those highly skilled in it, unless characters are using ropes, spikes, or other tools. Ice walls can only be climbed by characters using tools. The rate of a character’s movement when climbing on a slanted surface depends on the type of surface, the condition of the surface, the character’s class, and the character’s level of encumbrance.

Very Smooth surfaces include faces of smooth, uncracked rock, wooden walls with no accessible cross beams or other
handholds, and metal walls where individual plates of metal have been bolted together. Completely smooth walls, such as a single sheet of metal, cannot be climbed without tools.

Smooth but Cracked surfaces include most types of masonry, a typical cavern or dungeon wall, or a cliff that is not subject to a great deal of weather erosion. Castle walls, towers, and city walls that receive regular maintenance fall into this category.

Rough surfaces include most natural cliff faces, constructed walls that have not been maintained regularly, and most wooden walls or stockades. Any kind of masonry using natural stone instead of bricks or blocks will form a rough surface.

Rough with Ledges surfaces include hand- and footholds of three-inch width or larger, or provide some other kind of usable route. A cliff that has been steadily eroded by frost, or a chimney (a crack that a climber can follow up a slope, pushing off against each side with his hands and feet) will provide a rough surface with ledges. Also, stone buildings that are approaching a state of ruin often create this sort of climbing surface.

Ice Wall surfaces are sheer surfaces made mostly or entirely of ice. They are treacherous, and even thieves cannot climb ice without tools.

Pole surfaces include poles made of any materials, tall slender trees with few branches, and free-hanging ropes. A pole’s diameter cannot be greater than 1/4 the height of the character attempting to climb it, unless the character uses a rope. Any pole with tree bark still attached is considered a nonslippery surface. A rope only falls into this category if the character cannot brace his feet against a wall or some other surface to aid the climb.

Tree surfaces include any trees where branches are plentiful enough to provide handholds, or any constructed object of girders or a similar grid, such as scaffolding.

Rope and Wall surfaces include any situations where a character can climb up a rope and brace his feet against a wall or some other vertical surface as he climbs.

Sloping Wall surfaces represent areas that do not quite qualify as vertical, yet are too sloped to allow normal walking. Like all types of climbing, a character’s chance of success assumes that he has both hands free. If a character falls while on a sloping wall surface, he can make a saving throw vs. petrification; if the save is successful, he takes no damage from the fall. Even if the save is unsuccessful, the fall only inflicts half of the normal damage.

Nonslippery surfaces are dry and solid. They do not crumble when touched, and a character’s chance of falling is calculated at the normal rate.

Slightly Slippery surfaces are wet or crumbly. The chance of a character falling from a slippery surface is twice normal.
Slippery surfaces can be places where water runs regularly, or surfaces covered by slime or algae, or those coated by a thin layer of frost, ice, or grease. A thief character’s chance of falling on a slippery surface is ten times his normal chance.

Encumbrance also plays a major role in the success of a character’s climb. Encumbered characters cannot climb sheer surfaces without the aid of tools. Characters with heavy gear or very heavy gear move at the movement rates listed for climbing characters. This halving is cumulative with all other effects. Characters with no gear or normal gear can utilize the full climbing movement rates.

Characters cannot climb in any type of plate mail armour, nor can a shield be held by a climbing character. Characters in chain, splint, scale, or banded armour can climb, but suffer a -3 penalty to their chance for success. Characters in studded leather or padded armour suffer a -1 to their chances. Leather armour does not penalize a climber. A character can sling a shield over his shoulder to carry it along while climbing; he cannot receive any defensive benefit for a shield thus carried.

Certain tools can be used to aid characters making a climb. Tools serve both to increase the chance of a climb’s success and to decrease the chance of a character getting hurt in a fall. The disadvantage of tools is that they considerably lengthen the time needed to make a climb, and often make enough noise to attract unwanted attention. This noise is the main reason that tools are not commonly used by thieves in the pursuit of their usual missions. Two types of tools, the grappling hook and the spike, or piton, can be used to aid a climb. Both must be used with a rope to have any effect. Spikes can be hammered into a wall surface and used to anchor a rope that subsequently protects a climbing character against falls. The character must have a hammer, and must spend D4 rounds pounding in a spike. The clanging of such activity can be heard up to a kilometre away in windless conditions. The usual function of a spike is to shorten the distance that a character falls, should such an accident occur. Increasing the protection is the fact that any character whose fall is broken by a rope suffers only the damage a fall of that distance would normally inflict.
Whenever a spike is called upon to arrest a fall, as in the above example, there is a 10% chance per character supported that it will give way. For example, if two characters are roped together and relying upon a spike to arrest their fall, the spike has a 20% chance of popping free. If the spike comes free, the characters fall the full distance to the ground (or twice the distance to the next spike). Characters can help prevent such accidents by using more than one spike. Climbing an ice wall is a dangerous act that absolutely requires the use of spikes. In fact, a spike must be driven into the ice wall before a character can climb. This process must be repeated each round, and since it takes a round to drive a spike, the process is doubly slow. In addition, spikes placed in ice have a 15% chance of pulling
free per character whose weight suddenly pulls against it.

Ropes are discussed as climbing tools in combination with spikes and grappling hooks, but there is one situation where rope alone can serve a character as an effective climbing tool. This happens when a character wishes to climb a pole that is of too great a diametre for him to ascend unaided. In this case, the character can wrap the rope around the pole and pull against it as he climbs. This technique can be used to climb a pole whose diametre equals the character’s height. Any pole wider than this should be treated as a wall.

Grappling Hooks are relatively heavy iron tools with at least two, and usually three or four, separate hooks branching from the end. The hook is designed to be thrown, and to catch on protrusions and thus support a rope and climber.
A character can throw a grappling hook upward a distance equal to his Strength score (rounded up) times 10. The horizontal distance that a grappling hook can be thrown equals the vertical distance, unless the character has enough room to swing the hook in a circle several times before the cast. In this case, if a character has a radius of 3 metres
from his body cleared of obstacles, he can throw the hook twice as far horizontally as he could otherwise. A character can throw a grappling hook once per round. If the cast is unsuccessful, it takes another D4 rounds to coil the rope
and prepare the hook for another throw. The chance of a grappling hook catching on its intended target is treated as a Thac0 roll. A thrown grappling hook does not make as much noise as a hammered spike, but is not silent. A successful throw is audible for 30-120 metres in ideal conditions; an unsuccessful throw will raise a clang audible 60-240 metres away.

Rappelling is a means of hastily descending a sheer surface by means of a rope attached at the top. The character lets the rope wind around his body and uses the friction of the rope to slow his descent. In order to rappel successfully, the character must make a successful Climbing Check. Failure means a fall from the top to the bottom of whatever distance is involved. A character can rappel up to 36 metres per round. All normal climbing restrictions apply (encumbrance, armour, etc.).

The normal damage caused by falling is based on the premise that the character lands on a smooth, but hard, surface. Obviously, different surfaces cause differing amounts of damage. Rough landings deposit the unfortunate character on a surface of broken rocks or other debris, or a slanted surface that sends the character ricocheting off to the side. Landings on a rough surface inflict double the normal damage from the fall. Spikes or other weapon-like features of a landing area inflict damage beyond that caused by the fall. Such damage is determined by how closely packed the deadly obstacles are: usually each spike causes an extra D6 of damage. When spikes or other obstacles are placed in an area, the GM should choose a number of dice to reflect how closely the spikes are packed. A D6 group
of spikes means that a character will impale himself on 1-6 of the spikes when he falls, while a 3D6 grouping indicates spikes that are much more densely packed. A character striking them will suffer from 3-18 D6 of damage in addition to that inflicted by the fall. Soft landings include yielding surfaces such as sand, mud, soft loam, pine branches, or flesh. A character fortunate enough to make a soft landing takes only half the damage that the fall
would normally inflict. Very Soft landings generally result from some sort of prepared cushion of feathers or straw, etc. Occasionally a character might be fortunate enough to fall into a very soft landing without planning for it, but this is very unusual. A character making a very soft landing can make a saving throw vs. paralyzation. If the save is successful, the character sustains no damage at all; if it is unsuccessful, he takes half the normal amount of damage for the fall. Water landings can be virtually painless if a character lands correctly, but can be every bit as damaging as a fall onto hard stone if the character does a belly-flop or lands on his back. When a character falls, he can attempt to make a Dexterity Check if he suspects or knows that he will be landing in water. If the check is successful, the character takes D6 of damage for every 30 metres of the fall, rounded up. If the check is unsuccessful, however, the character sustains the normal damage from the fall. A character cannot attempt to stop a fall by catching onto a
climbing surface and make a Dexterity Check to land in water during the same round. If the fall lasts more than one round, he can attempt a Dexterity Check on the second round.

The movement rules provide a means for all characters to scramble up and down sheer surfaces to a limited extent, but engaging in combat while suspended on these surfaces is another matter entirely. Characters who engage in melee or missile combat while on a sheer surface suffer penalties to combat abilities, and have an increased chance of falling during the fight. When climbing, a character loses all bonuses to his Armour Class that would come from a shield or Dexterity bonus. If the character’s face is toward the surface, he presents his back to any attacker except one that is next to him on the wall, with the attendant penalties. Additionally, such a character can only face a foe to one side or the other. Since at least one hand is needed to hold on, the character cannot use multiple weapons. Finally, a -2 penalty is assessed to all of the character’s attack, damage, and save rolls. If combatants are above or below their opponents during a fight on a wall, specific modifiers apply. The higher character gains a +2 “to hit” modifier in addition to all other modifiers that apply, while the lower character suffers a -2 modifier to his attack rolls.
If, in the GM’s judgment, the character can reach a place of some security before engaging in combat, some or all of these penalties may be cancelled out. An archer who carefully selects a ledge from which he can easily see his targets and draw his bow should be able to fire normally. Likewise, a swordsman firmly balanced on a large boulder should have an advantage over opponents who are scrambling up to reach him. When a character on a sheer surface is struck for any amount of damage, the character must make an immediate Climbing Check. If the check succeeds, the character remains in place; if it fails, the character falls. A -10% modifier applies to the check if the damage inflicted by the attack is equal to or greater than 1/2 of the character’s total hit points (rounded up). Creatures defending a wall or cliff often roll or drop heavy objects onto attackers below. An average-sized boulder (90cms in diametre) inflicts 2D8 points of damage to anyone it strikes. If the creatures dropping the missile are unable to pick it up and hurl it (as a giant could), they suffer a -8 modifier to their attack roll. If the victims are climbing a sheer cliff, they could be knocked off by this attack, as given above.

The situations covered so far all assume that a character has enough room to stand somewhere without using his hands to hold on. The following rule is applied if some sort of drop-off is located within 1.5 metres of the character.
All of the difficulties associated with this type of combat relate to hits against the character; there are no penalties for attacking in this situation. If a character gets hit by any attack that causes a loss of hit points or consciousness (such as a sleep spell), he must make a successful Dexterity Check to avoid falling over whatever dropoff is nearby. The character’s Dexterity, for purposes of this check, is increased by two for every foot of distance between the character’s feet and the drop-off. The character’s Dexterity should also be modified if the force of the blow pushes him toward or away from the drop-off. In melee combat, a character with his back to a wall receives a +2 modifier to his Dexterity, while a character with his back to a drop-off receives a -2 penalty. During missile combat, the path of the missile serves as a good indicator of whether a character is pushed toward or away from a drop-off. For example, a character who is standing on a narrow bridge and is struck by an arrow fired from his left side will obviously be propelled toward the drop-off on his right. A character fighting on a ledge, on the other hand, with his back to the wall and his enemies before him, is pushed back toward the wall by the force of any blow. The modifier for such situations is a + or -2 to the character’s Dexterity, applied in addition to all other modifiers.

If a character is fighting in extremely close quarters and falls from either a sheer surface or a narrow ledge or bridge, he can sometimes drag his opponent along with him. This rule is only used when at least one of the characters is fighting with a weapon of less than 60cms in length, or when the characters are grappling. A character who falls while engaged in such a fight can make one attempt to grab his enemy as he falls. The character must roll a normal attack roll on D20, and get a result that would hit the other character. The target character receives no benefit for armour or shield. He is AC 10 minus Dexterity bonuses. No magical bonuses for weapons apply to this attack roll; in fact, any weapon held must be dropped for the attempt to be made. If the attack roll is successful, the character has grabbed some part of his opponent’s body. The character who has been grabbed must roll a Climbing Check (if on a wall) or a Dexterity Check (on a ledge or bridge) to see if he accompanies his opponent in the fall. If the check is successful, the grabbed character retains his position, with his opponent clinging tenuously to his leg (or whatever). If the check fails, both characters plummet to the fate that awaits them below. If the characters do not fall, the fight continues. The character who is hanging onto his opponent cannot make any attacks. Instead, he can make a Climbing Check (with a -2 modifier) to see if he can regain his hold on the wall or his footing on the ledge. If this check is successful, the character has regained his place; if unsuccessful, he remains clinging desperately to his opponent. The opponent, meanwhile, can attack the clinging character normally. Any successful hit requires the victim to make another Climbing Check with a -2 modifier. Failure means that he falls and his opponent remains on the wall. Of course, if anything else causes the character who is retaining his hold to fall, both characters fall. Even if characters are grappled together when they fall, they separate immediately. Thus, a magic-user might be able to cast a spell before hitting the bottom, while his less fortunate opponent plummets to a hard landing.

A common defensive barrier in caves is the bottleneck passage where only one or two characters can hold off a mob of attackers. This tactic limits the number of enemies that can attack at once. This bonus is of course usable by monsters and NPCs as well. It reflects the fact that a fighting individual can use such a location defensively, as protection from the enemy’s attacks, or aggressively, as a means of striking the enemy at an advantage. The side claiming the bonus must have sufficient room for all fighting individuals to use their weapons without interfering with each other.

Characters who cannot see in the dark run serious risks when participating in combat under these conditions. Such characters suffer a -4 penalty to all attack rolls, saving throws, and damage rolls, as well as a +4 penalty to Armour Class. Even with this penalty, a successful attack cannot cause less than 1 point of damage. Also, all bonuses that require a character to see his victim are forfeited. These include such abilities as a ranger’s bonuses against giants, a thief’s backstab attack, and a vorpal sword’s beheading function. Not only do characters who are unable to see have greatly reduced chances for success in combat, but they stand a chance of wounding an ally or striking some other obstacle in the darkness, or encountering treacherous terrain features such as cliffs, pits, or pools. These penalties do not apply to characters with infravision, nor to those wielding magical weapons or within range of any source of light.
If a character who cannot see is within twice his weapon length of any ally, other opponents, walls, chairs, or other obstacles, his attack stands a chance of striking one of these instead of his target. If the attack roll misses with a modified result of 0 or less, the attack has unintentionally struck another object. Any object closer to the character than twice his weapon’s length may be hit. Count up all the objects within the weapon’s reach, then roll randomly to determine which is hit. In addition, if a character who cannot see fights next to a dropoff or on a sheer surface, his Dexterity is reduced by two for purposes of all Dexterity Checks to see if he falls over the drop-off, and his Climbing Rating is reduced by 10% for purposes of all Climbing Checks. If a spellcaster cannot see the target of his spell, there is a chance that the spell might affect something besides the intended target. In these situations, the player must indicate exactly where the spell is targeted. If the spellcaster has a clue to the location of the target (noise or smell, for example), the GM may assign a -1 to -3 modifier.

The environment, both physical and psychological, which characters are confronted with beneath the surface of the earth is as much a hazard to their lives as the monsters who dwell there. There are numerous examples of adventuring parties who could overcome almost any monster which the forces of darkness might hurl against them being killed by a massive tunnel collapse or suffocating as a raging dungeon fire stole the oxygen from their lungs. In this section, we will examine life underground and give you, the dungeon master, a few interesting insights on the evils lurking there. Dungeons and other underground complexes touch a note deep within all of us. There is a certain fear or uneasiness associated with subterranean realms which even the bravest explorers must admit to at some point. Perhaps the most dramatic psychological aspect of a dungeon quest is that it places the characters in a situation where they are cut off from the rest of the world. In some cases, this sense of isolation is founded simply
on the knowledge that they have travelled several hundred metres beneath the surface of the earth and are not likely to encounter anyone else here. At least, not anyone who doesn't want to use them as target practice or the main course at a monster buffet.' In other cases, the sense of isolation may be reinforced by a physical barrier which impedes not only any chance of rescue, but any chance of a quick escape. Examples of physical isolation techniques
might include a cave-in which seals off the route which lead the party to this point or a series of iron gates which have slammed shut behind them. Another aspect of the dungeon style adventure is the fact that it forces the characters to confront an environment which is quite alien to them. There are numerous hazards which exist underground and not on the surface world. Although any of these hazards might be easily dealt with and discounted in a more familiar setting, the fact that they all exist simultaneously in the vast reaches of the underground can be quite overwhelming to a character.

The types of mines that are commonly encountered include placer mines and underground (or tunnel) mines. The strip mining common in the modern age requires heavy equipment. Placer mining involves sifting gravel, dirt, sand, and water from a flowing stream or river. Most commonly employed above ground, placer mining is a relatively simple mining operation. At its most basic level, the only requirements are a character with a shallow pan and a great deal of patience. A placer mine gathers the mineral content of an underground vein of metal that has been eroded by water and has flowed downstream. It finally collects in some part of the streambed, where the miner separates it from the water. Because only the mineral wealth that has been eroded from the ground collects along the streambed, placer mining is not the way to discover a lode of significant value. Operating an underground, or tunnel, mine requires a great deal more work than a placer mine-but the potential for wealth is much greater. An underground mine consists of a tunnel excavated into the earth. The rock that is dug from the tunnel is examined for riches. Because this book deals solely with the underground, the rules on mining deal primarily with tunnel mining. Of course, placer mining is still possible along underground streams, but underground characters and creatures are much more likely to labour in
the lucrative tunnel mines.

A mine tunnel must follow the shifting vein of a mineral through the earth. Such a path typically requires a 3 metre wide by 3 metre high tunnel. When a miner first discovers a mineral vein, roll D6. Multiply the result of this roll by 3; this is how far down (in metres) the tunnel must be dug to intersect the mineral vein. Once the vein is discovered, mining can begin in earnest. To determine the path of the vein, roll D4, with the result indicating the direction of the vein’s path as follows;
1 North-South
2 East-West
3 Northeast-Southwest
4 Northwest-Southeast
The vein always runs at least 6 metres in the direction indicated. After each 6 metre section of tunnel is excavated, the GM should secretly roll D8 to determine the path of the vein;
1 Steep Descent
2 Shallow Descent
3 Curves Right (10-60 degrees)
4 Curves left (10-60 degrees)
5-6 Continues straight
7 Shallow ascent
8 Steep ascent
Miners who wish to continue working the mine must follow the vein, even if it goes in a direction they would rather not follow. If the path of the vein takes a course that makes it impossible to follow, such as emerging into thin air through a sheer cliff face, that particular course of the mine has run out. Of course, the miners are free to follow the vein in the other direction. If both directions of a vein end, the mine provides no more minerals. In unusual circumstances, such as a vein ending in a cliff with a facing cliff across a narrow gorge, characters may attempt to pick
up the vein again across the gorge. The success of such an ‘attempt is left to the GM’s discretion; generally, the probability of such an occurrence is determined and a die rolled to see if the miners are successful.

A tunnel mine must be regularly protected with wooden or stone support pillars, called shoring, or else sections of the tunnel will almost certainly cave in. Shoring can be accomplished by characters with carpenter, stonemason, or miner proficiencies. As a general rule, each 3 metre section of tunnel requires two side braces and a ceiling brace. If the tunnel is the standard 3 metre wide and 3 metre high, this takes 9 metres of bracing that is at least 30cms in diameter. Each set of shoring supports takes four man-hours to construct. Unless the character doing the shoring is extremely strong moving the braces into the mine requires additional manpower or animal help.

When a miner successfully locates minerals, consult this section to determine type and quality.

The smelting of ore requires a fairly extensive collection of equipment. Because the ability to generate a very hot fire is crucial, smelters must have a bellows system as well as several unmeltable containers to hold heated ore. Most minerals require a coal fire for smelting, but some can be smelted by wood fires. A smelting operation produces much smoke and smell, so it is almost impossible to conceal. If done underground, the ventilation of the smelting area must be carefully attended, or the smelting fire is likely to consume all of the oxygen in the area. Gemstones rarely require the complicated procedures needed to smelt ore from rock, although occasionally the application of heat is necessary to remove excess minerals or rocks that are crusted around the gemstones. The usual finishing procedure for gemstones requires a character with gem cutter proficiency to cut and polish the stones. The drawback to this process is that a given character can only finish 2D20 stones in a day. Consequently, the rate at which the stones can be excavated usually greatly exceeds the rate at which they can be finished.

A given mine always contains a finite amount of mineral wealth. Occasionally, this amount is enough to keep a mining
crew busy for a lifetime or more; much more frequently, however, the mine plays out after a certain period of time. To determine how long before a mine’s wealth is depleted, the DM should secretly roll D100 at the start of the mining operation. The resulting number equals the number of man-weeks that the mine can be worked before depletion. If the resulting number was doubles (e.g., 11, 22, 33, etc.), however, the mine has a much longer duration. Roll D100 again, and this time read the result as the number of man-months that the mine lasts, adding this figure to the number of weeks already determined. If this second D100 roll also yields doubles, roll D100 a third time, and this time read the result as the number of man-years before the mine is depleted. Further doubles rolls are also rerolled to provide an additional number of years, until a D100 roll is made without a doubles result. For the sake of convenience, treat each month as four weeks and each year as 48 weeks, or 12 months, when totalling up the mine’s longevity. Note that man-weeks refers to the amount of work that one human miner performs in a week. If 12 miners are engaged in excavating a given mine, 12 man-weeks of the mine’s lifetime are used up every week of the mining operation.

Despite the tremendous amount of wealth that can be generated from a successful mining operation, this is definitely not a free lunch for avaricious player characters. Any mining operation includes an inherent set of hazards, and a very successful operation attracts additional problems almost automatically. The piece of land to be mined is often referred to as a claim, in that the miner claims the right to remove mineral or gemstone wealth from the ground. If the miner, whether player character or NPC, holds a clear and undisputable legal title to the ground in question, the claim is usually not a problem initially. Except in the most civilized and well-developed areas, however, a clear and undisputable title to land is an uncommon occurrence in a fantasy world. If anyone holds title to a piece of land, it
is usually a king or some other ruler who exhibits an understandable, if selfish, interest in the wealth of his land. It might be possible for a character to gain a mining charter from a ruler, allowing the character to mine a given tract of land. In this case, a hefty percentage of the mine’s profit must be turned over to the ruler. Such arrangements might call for as little as 25 or 30% to be claimed by the ruler, but more often require a 50% share to be turned over. The lower claims are only made if the ruler has a weak grasp on his kingdom and wishes to avoid conflict. A strong ruler always asks for 50% of the mine’s products. The ruler generally takes steps to insure that his fair share is turned over to him. These steps may include such tactics as placing a spy among the miners working the claim, surprise inspections of the mining site, or discreet observation of the operation from a relatively safe distance. Sometimes the character doing the smelting or finishing is in the employ of the ruler and loyally reports the exact amount of material processed. If a miner is caught cheating his liege, the punishment is usually death. If a ruler is inclined to show exceptional leniency, the character might be allowed to live-perhaps even retaining all of his body parts-but he will certainly not be allowed to continue to operate the mine. A claim made on a piece of wilderness land is free, at least initially, of the need to negotiate a charter with a ruler, but such claims have attendant problems of their own. Consider that the land is a wilderness most likely for One Of two reasons: either the land and its denizens are too savage for settlements to exist, or no one has discovered any useful purpose for that piece of land.

It is not at all unlikely that a piece of land, thought for centuries to be worthless, could become highly sought after by many different rulers, should the land be discovered to contain valuable mineral resources. In this case, the PCs might find themselves embroiled in a war for control of the land. Whichever ruler ends up in control will no doubt wish to exact a tribute from the miners on his land. If the PCs have aided the winning ruler during the course of the conflict, it is quite possible that they will be allowed to continue to operate the mine with taxes going to the ruler. If the PCs actively opposed the winning ruler during the course of the war, there is very little likelihood that their claim will be recognized. At best, they might manage to flee with their lives and some small profit from operations up to that point. Savage denizens present a fairly obvious hazard to would-be miners. Raiding monsters show no particular favour to PCs perceived to be trespassing on the monsters’ territory. Of course, if the monsters are somewhat intelligent and not inclined to take over mine operations themselves, it may be possible for the PCs to negotiate some kind of arrangement with them, similar to the charter that might be signed with a ruler. However, monsters, particularly chaotic ones, have notoriously little respect for such agreements; they might easily cancel the agreement with no more notice than a battle-cry or surprise attack. Even if an area is presumed to be wilderness, there is no telling who or what might think that they own it. To such landlords, legal or not, any kind of operations on their land are perceived as trespassing. Another hazard of wilderness mining operations is that the characters have no legal protection for their claim. Such a claim is generally owned by whichever creature or party is most capable of holding it against other interlopers or claim-jumpers. The number of claim-jumpers climbs in direct proportion to the profitability
of the mine, since the more money it makes, the more attractive it becomes to others. A mine that is producing considerable wealth might attract distant creatures or high-level characters whose only purpose is to try to take over the mine by force. A commonly attempted but rarely successful tactic for preventing these headaches is for the miners to attempt to conceal the mine. This virtually never works in a settled area, and has only a limited chance of success in the wilderness. Several problems must be overcome in order to conceal a mine from unwanted discovery. First, the mine itself must be hidden in such a way that it cannot be discovered by a creature that happens to pass nearby. Secret doors and piles of brush and twigs are commonly employed to hide a mine’s entrance. The tailings, or unwanted refuse from the mine’s excavation, often give away the location of a mine. The standard procedure is to simply dump excess rock at the mouth of the mine and go back in for more. If characters exert great care, they might be able to spread the tailings over a large area and keep the mine’s location a secret. The tailings could also be dumped into a river, lake, or deep pit. This requires more effort than the actual digging of the mine, however; if miners attempt to scatter the tailings, the rate of mining is no more than 25% of what it could be if all of the workers
were actually mining. The noise involved in chipping away at the stone of the mine can provide clues to its location, especially to creatures of the Underground. Few things are as disconcerting to a group of miners as to have a bulette burst into the tunnel between the miners and the outside world. If the mine is located next to a smelter, the characters had better abandon all hope of concealing the mine. The smelter produces such clouds of smoke and such a pervasive odour that concealing the claim is all but impossible except in the most remote and uninhabited areas. Even if the miners manage to operate the mine in complete secrecy, amassing a considerable fortune in mineral wealth, the
disposal of this wealth becomes a problem in itself. Characters who brazenly stroll into town, visit the moneychanger, and ask to convert 100 pounds of solid gold into coinage are certain to raise .a few eyebrows. Such reactions might be even more pronounced in the case of a gemstone mine. Any NPCs getting wind of the valuable claim could attempt to follow the characters back to their mine, or take other steps to learn its location.

In all likelihood, a PC or group of PCs cannot run a mining operation by themselves. Even if the party has a character with miner proficiency to supervise the work, finding enough strong arms to excavate a large mine usually requires hired help. In fact, if the mine’s claim is one of questionable legality, or if a sudden attack by monsters is a possibility, skilled adventurers are better used as scouts and guards for the mine, while low-level labourers perform the actual excavation. Hireling loyalty is not a significant problem in an iron or copper mine, but if a precious metal or gemstone find is being exploited, employees are presented with a great opportunity to steal from their employers. For this Loyalty Check, treat the foreman of the mining operation as the liege when determining modifiers to the roll. Additional modifiers can be applied to reflect the state of the mine’s security. For example, if all miners must submit to a search after a shift of work, the check would gain a +10% modifier, since this would deter the NPCs from theft. If, on the other hand, no PCs are present as the miners leave the mine after a shift, their loyalty rating might suffer a -10% modifier. For purposes of loyalty modification, the evaluation of the NPC’s pay should be based on the value of the mine. If the Loyalty Check fails, this does not mean that the NPC immediately fills his pockets with whatever valuables are at hand and makes a break for the high country. The GM must consider the Intelligence of the NPC and concoct a suitable plan for the theft. Only workers with low Intelligence, perhaps 8 or less, attempt a theft with no planning. If the NPC has exceptionally high Intelligence, he will go to great lengths to prepare for the theft and to either ensure his getaway or conceal the fact that the theft has occurred. The thief steals D6 x 10% of his daily output.

Some potential problems are inherent in any kind of underground excavation, and mining is no exception. Prominent
among these are the twin dangers of flooding, and cave-ins. Flooding can occur in a mine if the excavators accidentally tap into an underground body of water, or if the depth of the mine drops below the water table. The chance of digging into an underground body of water depends, of course, on the proximity of such bodies. The best way to adjudicate this possibility is for the GM to have a carefully drawn map of the area around the mine, including any concentrations of water. As the characters excavate and expand the mine, the progress of the various tunnels
should be noted with care on the GM’s map. If one of the tunnels should drive into a body of water, the mine floods rapidly. Any characters below the level of the water have a very difficult time escaping. Characters at the level of the flow have to race the water to the nearest exit, while characters above it should be able to make an escape with relative ease. After this kind of disaster, a mine is very difficult to work unless some means can be found to drain or pump the water away. Any mine that reaches down to the water table or lower slowly fills with water. While this situation is not life-threatening, it is serious enough to close a potentially rich mine unless some means of removing the water faster than it flows in can be devised. Cave-ins can be partially prevented by proper shoring of the tunnel, but cannot be eliminated entirely. A tunnel that has been shored at every 3 metre interval stands only a 2% chance per week of suffering a cave-in. A tunnel with no shoring whatsoever runs a 50% weekly chance of suffering a cave-in. If the tunnel has been partially shored, the GM must calculate a percentage chance of cave-in based on these two extremes. External forces can occasionally increase the chances of a mine caving in. An earthquake might add D4 x 10% to this chance, while a heavy rain or flood would increase the chance by D3 x 10%. Burrowing creatures such as umber hulks and anhkhegs increase the chance by 1% per hit die of intruding monsters. The location of the cave-in is randomly determined. The GM designates one end of the mine as 01, and the other as 100, and rolls D100. The resulting number indicates where along the path of the tunnel the cave-in occurs. Cave-ins automatically bring down a section of ceiling 6 metres long and 3 metres thick. Chain reaction cave-ins should be checked for normally.

While most of the Underground is exactly that, some locales possess sources of natural illumination.
Luminescent Growths: Rare forms of lichen, fungi, and moss are bioluminescent. In sufficient quantities, these growths can illuminate large caverns. Most bioluminescent growths are quite dim, so a cavern illuminated by glowing moss or fungi is typically as dark as starlight, although some particularly bright regions might be equal to moonlight.
Molten Rock: Areas with exposed pools or streams of magma are illuminated by the dim, ruddy glow of the molten rock. The glare of molten rock is typically equal to moonlight.
Radiant Crystal: Some rare rocks of the Underground are naturally radiant, ranging in brightness from starlight to full daylight, although daylight equivalence is quite rare. The great vault of Deep Imaskar is roofed with radiant crystal that is as bright as weak surface daylight.
Reflective Stone: While not naturally luminescent, caverns made partially of reflective stone can be much more easily illuminated by small light sources than normal. Reflective stone quadruples the radius of illumination of any light source brought inside.
Wizard Fire: The rarest and most wondrous of natural illuminations in the Realms Below, wizard fire consists of dancing sheets of dim light, like the northern lights of the surface world. Though it is only as bright as starlight, wizard fire is weird and beautiful.

Barrelstalk: Stout as a hogshead of ale, the barrelstalk is a large, cask-shaped fungus that grows up to 2.5 metres in height and 1.5 metres in diameter. Its outer layers are tough and woody, but its inner flesh is edible, and its centre is filled with a reservoir of water (usually from 6 to 15 litres) that can be tapped and drained. The inner flesh turns black and poisonous when barrelstalk begins producing spores, which happens after ten years of growth.

Bluecap: The grain of the Underground, bluecap fungus is inedible to humanoids, but its spores can be ground to make a nutritious, if bland, flour. Bread made from bluecap flour is usually known as sporebread. Bluecap seems to do well with or without faerzress, and most Underground humanoids cultivate it.

Cave Moss: Found only in faerzress-rich regions, cave moss is inedible to humanoids, but it is a favourite grazing food of some giant vermin, as well as rothé.

Fire Lichen: Pale orange-white in colour, fire lichen thrives on warmth, so it grows in regions of geothermal heat or near connections to the Elemental Plane of Fire. Fire lichen can be ground and fermented into a hot, spicy paste, which is often spread on sporebread to give it flavour. Duergar ferment fire lichen into a fiercely hot liquor.

Luurden: Luurden, or bloodfruit, is a rare tree that grows only in areas of strong faerzress. The barren branches of this pale, gnarled tree seem more dead than alive, but once every to 4 years, it produces a small amount of bitter red fruit that is used to make rare Underground wines and elixirs.

Ripplebark: A shelflike fungus that resembles nothing so much as a mass of rotting flesh, ripplebark is surprisingly edible without any special preparation, although it tastes much better if cooked properly. Ripplebark grows naturally in living caves.

Sussur: Rare and magical, the so-called "deeproot" tree is found only in the largest of caverns. It can grow to a height of 60 metres, and its branches are long and gnarled, with banyan like aerial roots. Few leaves grow on the sussur; it exists almost entirely on faerzress and is often found in caverns where wizard fire is prevalent, a sussur tree can drink in magic from its environs, so most sussurs are surrounded by antimagic fields that extend for hundreds of metres.

Waterorb: This bulbous fungus is aquatic. It grows in boulder-like patches underwater wherever the water deposits detritus.

Zurkhwood: This giant mushroom can reach a height of 9 to 12 metres. Its large spores are edible with proper preparation, but zurkhwood is important primarily because its stalks are hard and woody. Zurkhwood is one of the very few sources of timber (or anything like it) in the Underground, and many items that would be crafted from wood in the surface world are fashioned from zurkhwood in the Realms Below.

Bats: Better adapted to a life in darkness than most other animals, bats are extremely common in the Upperdark and Middledark. Only the lowest, most inhospitable reaches are free of these creatures, and even then, monstrous varieties such as dire bats and deep bats flourish. Near the surface, these creatures are simply surface-world bats that lair in Underground caverns. Titanic roosts that house many thousands of such creatures can be found in some spots. Lower down, most Underground bats are fungivores or insectivores.

Fish: Many of the rivers, lakes, and seas of the Underground are filled with cave fish. For the most part, such fish are small, pale, relatively inoffensive creatures. Most are blind, though some that reside in illuminated caverns may retain their eyes. In the larger bodies of water, subterranean versions of dangerous fish such as sharks may be found. Cave fish need something to eat, of course, so isolated lakes don't support cave fish populations unless they're large enough to support plant life that can survive in absolute darkness.

Lizards: The Underground is home to a variety of lizards, ranging from the poisonous spitting crawler to the wild varieties of pack lizards and riding lizards. Some are fungivores; others are dangerous hunters that can easily make a meal out of a human. Domesticated giant lizards are commonly used as beasts of burden and mounts in drow and duergar settlements.

Rothé: These grazing, muskoxlike creatures are well adapted Lfor life in the depths. Subsisting on fungi, moss, lichen, and almost anything else that grows in the Underground, rothé are highly valued by most Underground races and often kept in large corral-caverns.

Lungrot: This disease most often strikes air-breathing creatures that have been sealed inside ancient ruins. Once inhaled it reduced CON by D4 and STR by D3 per hour unless magically healed.

Scaleflake: This disease most often strikes aquatic or reptilian creatures, but anyone swimming, wading, or submerged in tainted water can contract it. Scaleflake manifests as swelling, oozing, smelly pustules coating the surface of the afflicted creature's body. It reduces CHA by D4 until healed.

Crysstone: Beautiful, intricate, and very delicate, crysstone is a rock that resembles spun glass. It is very hard but not at all durable (2 hit points per inch of thickness). Crysstone shatters easily, and sonic damage automatically bypasses its hardness: Because it is so susceptible to sonic damage, the threat posed by monsters with Wide-area sonic attacks increases in areas where crysstone is prevalent.

Darkstone: Darkstone seems to drink in light. In tunnels cut through this material, light sources dim, shedding a glow only half as strong as usual. Thus, a bullseye lantern illuminates a cone only 9 metres long and 10 metres wide, while a torch lights only a 3 metre radius. A daylight spell in a darkstone area radiates daylight in only a 9 metre radius.

Photogenerative Rock: These rocks grow quickly when exposed to light. In each round of exposure, a photogenerative rock doubles in size until it's sixteen times as large as it was when unlit (4 rounds). Eliminating the light halts its growth, and each hour of darkness reverses the effect of 1 round of light. Some Underground undead use photogenerative rock in their demesnes to stall light-bearing adventurers until the undead can ready their defences. Photogenerative rock can also be used to seal a doorway and divert light-bearers into more trap-ridden or better defended areas.

Photostatic Rock: Events that happen in the presence of this rock imprint upon it for a short time. One cubic metre of photostatic rock picks up impressions in a 3 metre radius and automatically relays them to anyone who touches it later. The effect is similar to that of a stone tell spell, except that the photostatic property reveals only what happened within its radius in the past hour. Every additional cubic foot of photostatic rock provides 1 more hour of memory and expands the radius of sensitivity by 3 metres. A photostatic rock records only what it witnesses (treat its perspective like a burst), so it cannot record what goes on beyond a closed door.

Quickstone: Quickstone is the Underground's answer to quicksand. Like many Underground features, it's much more terrible than its surface-world equivalent. Quickstone looks like solid stone and blends into the surrounding rocks, but it functions like quicksand except that the Difficulty Class for each manoeuvre increases by 5. Transmute mud to rock permanently solidifies quickstone, but a success on the spell's Reflex saving throw enables a creature trapped within it to escape.

Rock Gourds: These rocks have been warped by long-term proximity to a portal leading to the Elemental Plane of Water. Rock gourds are rare, naturally occurring stones, not created magic items, though they register as faint conjuration magic under examination with a detect magic spell. Shaking a rock gourd causes water to dribble out. The ability of these stones to produce up to a gallon of water per day apiece makes them highly valued commodities where water is scarce.

Sickstone: Sickstone glows with a nauseating, not-quite-green, not-quite-silver light that provides illumination to a radius of 12 metres. Any creature within the range of this illumination must make a saving throw each round or take D6 points of Constitution damage. A successful save reduces the Constitution damage to 1 point. Anyone in physical contact with sickstone takes a -4 penalty on this saving throw, and any Constitution damage it takes becomes Constitution drain instead. The damage caused by sickstone results from a magical disease, so creatures immune to magical diseases are immune to the effects of sickstone.

Slickstone: This rock is very smooth to the touch. Although it is natural stone, it functions at all times as if it had a grease spell cast upon it. An actual grease spell cast upon slickstone has no additional effect.

The Eon Energy Corporation

Genetech

H-Tech

MetaTech

The Prometheus Institute

The Sons of Anubis

Field Earth

Field Terrakinetic

Metamorph Copper

Metamorph Diamond

Metamorph Earth

Metamorph Iron

Metamorph Lead

Metamorph Magma

Metamorph Tin

Metamorph Titanium

Sandswim