Demons in the Library
Somewhere, in a long-forgotten dungeon or deep in the heart of an abandoned keep or some other ruin, lies a mages' library. This library, guarded by magically bound demons, contains valuable books, thousands in number, historical and otherwise, both magical and mundane. Getting inside is easy; getting out alive is the problem.
Encounter level 5 (9,900 XP + 200 bonus for optional skill challenge + variable bonus for active skill rolls)
1 bloodseep demon (B)
2 maw demons (M)
1 summoning circle trap (7 rupture demons)
1 optional mini skill challenge
I pulled this encounter from a recent campaign I ran my son through. He really enjoyed it, and I think others will, too. The Demons in the Library encounter can be inserted into any campaign you are running, just be sure to do two things. One, place the location deep inside a building or dungeon or some other place the PCs are exploring and two, make sure there’s another way out of the room leading into it because the library itself is a dead end.
The PCs find themselves in a room before a set of double-doors made of thick wood (DC18 strength to break down). Each door has an ogre’s face carved into it and a brass pull-ring that passes through the ogre’s nose. A single keyhole is located in a metal plate that overlaps both doors. This unusual mechanism is difficult to pick (DC25 thievery to unlock), but has no traps. When unlocked, the plate stays attached to the left door when that door is opened. The right door cannot be opened until the left door is opened. To open the left door the PCs have to turn the brass ring to unlatch it and then pull. After that, the right door can be pulled by its ring; the right door’s ring does not rotate.
Begin with the following read-aloud text as soon as the PCs open the library’s double-doors:
The doors drift silently open to reveal a pitch-black room that smells like musty, old books.
After that, if the PCs flash a light source into the room, read this:
The room, as much of it as you can see, consists of bookshelves, two tables, some chairs, and a pair of giant statues. Between a gap in the shelves before you lies a path that leads toward the statues. Overhead, vaulted ceilings arc right to left. They are at least fifty feet high at their highest point. More bookshelves, the free-standing kind, block your view to the rest of the room. To your right, about fifteen feet away, is a rolling ladder, and you see a second rolling ladder leaning up against the bookshelves straight ahead. In the room’s corner, is a table and a set of chairs. To your left, not far from you, is another set of table and chairs. Between them is a large, wide-open space that is covered in grey flagstone flooring. The statues, fashioned into the shapes of demons, are at least thirty feet high.
The library is inhabited by three demons. These demons are magically bound to the location with orders to protect everything in it from intruders. They will only pursue transgressors into the adjoining room, no further. If intruders flee beyond that adjoining room, the demons will instead return to the library to resume their vigilance. They fight to the death. In addition, if the room’s magical trap is set off by anyone or anything, including one of the three resident demons, it will begin summoning additional demons (up to seven rupture demons).
Note that it is possible for the PCs to maintain stealth upon entering the library and for quite a while afterward (DC13 stealth check) as long as they avoid the trap and make the effort to remain quiet. This check is much easier than it otherwise would be because the bloodseep demon is located near the back of the library, more than 20 squares away, with many large objects in the way. If the PCs draw to within 20 squares of the bloodseep demon increase the stealth check to DC15, and if they draw to within 10 squares of it increase the DC to 18. The chances of the maw demons noticing the PCs is much less, but they are closer to the library's entrance which offsets some of their poor perception (DC9 for them to notice the PCs when they first enter and DC12 if the PCs draw to within 10 squares of them). As soon as the maw demons notice the PCs and attack or the trap is set off, the bloodseep demon will become aware of the PCs as well. The reverse is not necessarily true, though. The maw demons will remain oblivious to the PCs unless the trap goes off or they make their own perception checks (or the bloodseep demon fails a stealth check). This is because the bloodseep demon will refrain from attacking and attempt to sneak up on the PCs and wait for the first few turns of battle (see “tactics” section).
PCs who are trained in religion or arcana have an additional option during this encounter. They can undergo an exorcism, if they wish, of the initial three demons (a mini skill challenge outlined below); if they succeed, the exorcism breaks the binding on the library and forces the three demons, not the rupture demons, to immediately return to the abyss. The exorcism will not work on the rupture demons because they are summoned and linked to the trap (not specifically bound to the library). They can only be exorcized by dismantling the trap or by physically destroying them.
Features of the Library:
- Lighting: The initial lighting in the library is total darkness.
- Giant statues: The 30’ giant statues can be climbed (DC15 Athletics), but they cannot be toppled. They also provide cover.
- Rolling ladders: They can be used to climb the bookshelves, walls, or statues up to a height of 20 feet (automatic). However, anyone on a ladder takes fall damage if the ladder is toppled while he or she is on it (combined DC10 strength check to topple a ladder that has a person on it, only one assist allowed). They can also be rolled into a victim as a two-handed improvised weapon (range 5/10), but must travel at least one square before they can cause this damage
- Book shelves: The 20’ tall bookshelves can be climbed (DC15 Athletics). They can also provide cover. In addition, shelves not braced against the outer walls of the room can be toppled (combined DC20 Strength with an unlimited number of people who can assist), creating a chain reaction that automatically knocks over all other shelves behind them. Only the shelves that are not against the outer walls can be toppled in this way. A toppled set of shelves causes 4D8+5 damage to anyone they fall onto. They also create difficult terrain to a distance of four squares in the direction they fall.
- Tables: The tables can provide cover to anyone crouched underneath or to anyone behind them if a table is turned on its side (automatic).
- Chairs: Chairs can be used as two-handed improvised weapons that can also be thrown (range 5/10)
- Red couches: They can provide cover to anyone crouched behind them.
- Invisible square runes (trigger for the trap): Anyone standing in or adjacent to a square that contains the runes near the double-doors sets off the magical summoning trap (see below).
- Summoning circle (where the demons appear): This marks the location where rupture demons appear (one per round) after someone sets off the magical trap near the library's entrance.
- Books: Many of the books are individually valuable. PCs who examine the whole library should, after many days of searching, find several books worth 500 GC, dozens that are worth 100 GC, hundreds worth 50 GC, and thousands worth 10 GC. The books are heavy and awkward, though, so figuring out a way to pilfer more than a couple dozen of them will be difficult. A quicker search that is conducted in a few hours time will still allow the PCs to find some valuable books (you'll have to improvise, though, and perhaps give them a number based on the results of a perception check). In addition, a careful two-hour search of the library (DC25 perception) will also reveal a small section of books near the back of the library that contains rituals of 10th level and lower. Next to those is a dozen scrolls of 6th-level or lower rituals. If PCs succeed at a detect magic attempt at the back of the library (DC22 arcana), they will automatically and immediately locate the scrolls.
Initial Passive Checks (PCs can also make active checks if they wish):
- DC12 perception: Characters who succeed at this check notice a small patch of translucent green goop to the left of the door on the floor when they first enter.
- DC15 perception: Characters who succeed at this check hear the tiniest whisper of movement at the far end of the library.
- DC20 religion or dungeoneering (perception can assist, and so can the primary skill not used for the main check): Characters who succeed at this check sense something evil lurks in this room.
- DC 26 perception or arcana (dungeoneering and thievery can assist if the PC is also trained in them, and so can the primary skill not used for the main check): Characters who succeed at this check notice something unusual about the flagstones ahead of them. They see a faint sheen, but only if they look at the floor from a certain angle or squint their eyes to look at them with the corner of their eyes. To know more, they will need to go closer and examine them.
Unlocked Passive/Active Checks:
- DC15 nature, arcana, religion, or dungeoneering (any skills on this list that are not used for the main check can assist, but only if the PCs are trained in them), requires a standard action: Characters who examine the green goop can make this check to partially identify the substance they found as being something unnatural from another world or plane; it appears to be some sort of noxious contact poison. A DC20 arcana or religion check (all other skills on the list given above can only assist and only if they are trained in them) further identifies the substance as being from the abyssal plane, probably the secretion of some sort of demon. A DC25 arcana or religion check (all other skills on the list above can only assist and only if the PCs are trained in them) tells them that they believe it comes from a bloodseep demon, and they will know everything there is to know about this demon as outlined under the monster lore checks
- DC 28 perception, arcana, or religion (dungeoneering and thievery can assist, but only if the PCs are trained in them, and so can the primary skills not used for the main check), requires a standard action: Characters who notice something unusual about the floor as outlined under the initial passive check section can carefully approach the trapped runes (must be within 2 squares of it) and use either a passive or active result to notice four magically concealed lines of abyssal runes scrawled into the floor in front of them and a larger rune at the center. If they step onto one of the hexes of the runes, though, or within one hex of them, they set off the trap, and the runes will immediately become visible. They do not know anything else about the runes unless they can read abyssal or succeed at one of the other passive checks below. The symbols form the shape a square with the larger rune at their center.
- Read Abyssal, requires a minor action: Any person who sees the magically hidden runes and can read abyssal will automatically know what they say. They immediately know how the trap works and that there is a summoning circle somewhere in the library.
- DC 22 arcana or religion (thievery and dungeoneering can assist, but only if the PCs are trained in them, and so can the primary skill not used for the main check), requires a standard action: Characters who see the hidden writing but cannot read it can still make a follow-up check. If they succeed at this, they know that the glyph and writings activate something, but they do not know what, and they do not know if it will be helpful or harmful. In addition, if they qualify for a DC26 check using the same skills and limitations, the characters who make the check will identify the writings and glyph as a trap that is linked magically to a summoning circle/ritual somewhere in the library and will know that the summoning circle consists of a level 8 demon summoning ritual that will summon seven rupture demons. They can then attempt to disarm the trap using either arcana or religion, if they wish (see the trap section, below), or they can automatically provide someone else with a +4 bonus to Thievery checks made to disable the trap.
- Detect magic attempt (DC24 arcana, must be trained), requires 1 minute. PCs who make this detect/sense magic attempt and are successful will notice magic radiating from the location of the runes and the immediate squares around them, but they will not yet see the actual writing (unless they make the appropriate skill checks above). It is also unlikely they will detect the summoning circle, at least not yet, because it is too far away and likely out of their range, but that can change if they move closer to it. Either way, they can then attempt to identify the properties of the magical effect/ritual using the arcana skill again if they wish (DC24, must be trained) as a standard action, and if they succeed they will identify the trap and how it works and how it is connected to a summoning circle somewhere nearby. They will still need to disarm the trap, though, if they wish to make it nonfunctional. They can then attempt to disarm the trap using either arcana or religion (see the trap section, below), or they can automatically provide someone else with a +4 bonus to Thievery checks made to disable the trap.
Monster Lore Checks (make a passive/active check as soon as the PCs see each type of demon):
- Exorcism knowledge check (DC12 arcana or religion check, but must be trained): As soon as the PCs realize they are up against the either the bloodseep demon or maw demons, this passive or active knowledge check will inform them they have the option to undergo an exorcism skill challenge to break the binding on these demons and force them back to the abyss (see the “demon exorcism” mini skill challenge section below).
- Bloodseep demon (DC15 arcana or religion check): As soon as the PCs see the bloodseep demon they can learn more about it. If they make this roll, they will recognize its name, type, and keywords. They will also know a bloodseep demon likes to weaken its foes before facing them in combat, such as by tainting enemy food sources. If the PCs make a DC20 arcana or religion roll, they will know its powers. If they make a DC25 arcana or religion roll, they will know its resistances and vulnerabilities.
- Maw demons (DC15 arcana or religion check): As soon as the PCs see the maw demons they can learn more about them. If they make this roll, they will recognize their name, type, and keywords. If the PCs make a DC19 arcana or religion roll, they will know that maw demons are rather dull-witted, and that they prefer to feast on food over engaging enemies in combat. Hunger, not anger or bloodlust. drives them into combat. It's said that a piece of meat might distract a maw demon long enough for opponents to retreat. However, these creatures prefer the flesh of a living creature. If the PCs make a DC20 arcana or religion check they will also know their powers. If they make a DC25 arcana or religion roll, they will know their resistances and vulnerabilities.
- Rupture demons (DC12 arcana or religion check): As soon as the PCs see the rupture demons they can learn more about them. If they make this roll, they will recognize their name, type, and keywords. They will also know that rupture demons are oily things made of liquefied evil. Barely sentient, rupture demons never work for themselves or have their own plans. In any place where a rupture demon is found, it's certain that a more powerful demon lurks nearby. If the PCs make a DC17 arcana or religion check, they also know their powers. In addition, they will know that rupture demons are the weakest spawns of Juiblex, the demon lord of ooze and slime. Sages speculate that the rupture demons' aiding of other demons through their deaths must be part of some scheme by the enigmatic demon lord. If they make a DC22 arcana or religion roll they will also know their resistances and vulnerabilities.
Trap, level 8 warder (350 xp for the total value of the demons that are summoned)
The trap’s trigger is the set of runes located just inside the entrance of the library. They cover an area 10 feet by 10 feet in size and consist of magical runes and a glyph that are scrawled into the floor in the shape of a square. Normally, the writings are invisible to the untrained eye, but they can be detected by an astute PC with good perception (see “passive checks,” above) or with a “detect magic” attempt (see “unlocked passive/active checks,” above).
Whenever a creature enters one of the squares containing the glyphs or a square adjacent to the glyphs all the glyphs will immediately become visible. After that, the PCs will hear a loud popping noise and notice a bright flickering light at the center of the library. They will then hear another popping noise at the beginning of each round after that (the sounds of a new rupture demon being summoned). Each rupture demon is summoned in the middle of the circle at the center of the room, not where the trigger runes are. The rupture demons will then mindlessly rush toward the front of the library to attack the first PC they see. A maximum of 7 demons will be summoned this way.
Note that if PCs enter into a battle with the other demons in the room without setting off this trap or dismantling it, the bloodseep demon will find a cunning way to purposefully step onto the runes during the battle to set it off (see "tactics" section). The maw demons, on the other hand, do not bother to think of this. The rupture demons will not attack the other demons, even if they set off the trap.
Whether or not the trap has gone off, an adjacent character can use a standard action to disable the glyphs with a DC29 Arcana check or DC31 Thievery check (the skill not used for the main roll can assist, and so can dungeoneering, but only if the PCs are trained in them; in addition, it is possible for the PCs to automatically gain a +4 bonus to assist thievery instead of the +2 assist with Arcana, as outlined under the “unlocked passive/active” section). PCs can attempt to disable the trap as many times as they wish, but each attempt and each assist costs them a standard action, and only one attempt can be made per turn.
To disable the trap, the PCs must be adjacent to it; that means the trap will immediately go off if it has not yet done so, but that won’t matter if they succeed. Once the trap is dismantled, all rupture demons, even the ones already summoned, will disappear. They are immediately exorcized back to the abyss.
Demons will attack using the tactics below. However, it is possible for stealthy PCs to avoid detection (see the “DM information” section at the beginning of the article).
Bloodseep demon tactics (MM2, page 53):
On turns 1-3: After it notices the PCs, the bloodseep demon will move slowly and carefully toward them (using teleport movement because it is silent and a little faster). It will remain hidden for the first three turns, hoping the PCs will set off the trap and begin to summon rupture demons. It will also wait for the maw demons to attack.
Turns 4-5: The bloodseep demon will watch and wait until one of the maw demons is injured before it makes its first attack, but will defend itself if it is seen. Should it succeed in obtaining surprise it will use its weeping poison and claw attacks, preferably against a PC who is standing alone. Otherwise, it will use its normal teleport movement to appear near the other demons so its aura can affect them and the PCs. It will also use poison blast and its claw attack on one particular enemy, using the other demons as a buffer against the other PCs. It will also use its poison blast and aura to heal injured demons.
Turn 6: If the trap in the room has not yet been activated or dismantled, the bloodeseep demon will attempt to set it off. It will do this by scrambling toward it or teleporting onto it. If the trap has been set off or disarmed previously, the demon will instead proceed to using tactics as outlined under turn 7, below.
Turn 7: The demon begins to order the rupture demons to use demonic infestation to boost injured demons, including itself, while continuing to use poison blast and claw attacks. If no rupture demons are left or the trap was disarmed, it will instead proceed to using tactics as outlined under turn 8, below.
Turn 8: The demon will use poison portal strike to reposition itself on the battlefield to a location that will allow it to attack a single outlying PC and place it near its own demon allies so they can act as a buffer against the rest of the PCs.
Turns 9+: The demon tries to keep as many of its fellow demons near itself as it can (to heal them with its aura). It also continues using poison portal strike whenever it recharges. It also likes to teleport on top of the standing bookshelves or the statue's shoulders to stay temporarily out of the PCs reach after each use of its poison portal strike, but only if it hits (which allows it to conduct a second, follow-up teleportation).
Maw demon tactics (MM3, page 42):
A maw demon’s tactics are as simple as its appearance suggests. It rushes the nearest bloodied creature or, if there isn’t one, rushes the nearest uninjured creature. Once it smells blood, it will pursue that creature single-mindedly and chomp at it until it stops moving or is no longer bloodied. It will then rush the next victim, preferably another bloodied PC, and do the same. It thinks little during the battle, but if the maw demon is ever bloodied it will demand a nearby rupture demon to use enveloping embrace against an enemy so the maw demon can regain some of its lost hit points.
Rupture demon tactics (MM2, page 60):
A rupture demon possesses little sense of self and virtually no sense of self-preservation. It wades into melee, attacking any creatures that attack it. It uses enveloping embrace when it can cause maximum destruction or when a more powerful, intelligent demon demands it to do so.
Demon Exorcism (optional mini skill challenge):
Level 5 (award the PCs a bonus 200 XP if they pursue this option and succeed at it)
Complexity 1 (requires 4 successes before 3 failures)
Primary skills: Religion (must be trained), Arcana (must be trained)
Secondary skills: A primary skill not used for the main roll can be used to assist instead (must be trained)
DC for each success: 18
Players trained in the religion or arcana skills can conduct a mini skill challenge during the battle that will break the library’s binding and exorcize the library’s three original demons to the abyss. Each attempt at a success requires a standard action, as does each assist, and only one attempt can be made per turn. The exorcism does not work against the rupture demons, though, which are summoned by the room’s trap and are bound to the trap not the library (see the trap section, above, for how they are exorcized). To attempt an exorcism or to assist another at it, the PCs must be trained in the primary skill used. Each attempt is a DC18 check. If three failures are obtained before four successes, the skill challenge must be started completely over.
In addition to the experience for the encounter and possible bonus experience for the optional skill challenge, reward PCs bonus experience points for every active skill check success they made. Only give experience for active skill check successes, though, not for passive ones. This is because PCs do not learn from a task they can do sleep-walking, and only when they stretch their abilities to the maximum do they learn something and experience growth. This reward is 50 XP per active success, but rolls made during the actual skill challenge are not counted.