The Prison Cube • Odyssey of the Dragonlords

This gargantuan iron cube, 200 feet on each edge, hangs from five massive chains. The center chain has a strange contraption attached to it: an hourglass made from transparent adamantine. About two thirds of the sand inside is in the bottom half of the hourglass, while the rest pours slowly down. Inside the cube is one of the weapons of the gods, a Tarrasque. There are also primordial golems that have existed since the creation of the cube. These undying constructs are there to protect the workings of the cube and make sure that the Tarrasque is fed.

History of the Cube#

While Lutheria was originally ordered by her father Kentimane to watch over the weapons of the gods, she has tricked an ancient Ice Devil to do the work instead. Lutheria deceived the creature by promising him dominion over an eternal kingdom in the Nether Sea. The ice devil is bound to the cube until Lutheria dies, or until she releases him from his oath.

Cube General Features#

The inside of the cube is strangely cold and alien.

Ceilings. The ceilings are 15 feet high, unless otherwise noted.
Doors. All of the doors are made from iron.
Lighting. All of the rooms are unlit.

illustrated quote — We know that the Titans possess powers that have yet to be revealed. My mother forced them into a stalemate before they ever became desperate enough to unleash such horrors. But the time may yet come when we learn what was locked away at the dawn of time. —Vallus, Goddess of Wisdom

Cube Key Locations#

B1: Entrance#

At the very top of the gargantuan iron cube, there is a complex contraption like a massive hourglass that stands more than 30 feet tall. Sand empties from the top half of the hourglass into the bottom half, with aching slowness. Drilled into one corner of the cube’s surface, there is a circular portal of black metal.

The door at the corner of the iron cube is the entrance. It is a circular hatchway made from adamantine, and it is invulnerable to damage. The only way to open it is to speak the primordial word of power that was used to create the cube. This word can be learned from the living Titan on Titan Island (area N3). The Legend Lore spell can also be used to reveal it.

The primordial word is pretty much unpronounceable by mortals. It will appear in a hero’s mind, be used once to open the portal, and then vanish. The players don’t

actually need to know or speak the word. They only need to know that it exists in one hero’s mind.

The Hourglass. A successful DC 20 Intelligence (Arcana) check reveals that it will take three centuries for all the sand to run into the bottom of the hourglass. This is some sort of timing mechanism. Eventually, the creature imprisoned inside will awaken and return to the surface: this happens once every thousand years.

B2: Entry Chamber#

As you descend the spiral staircase and enter the chamber below, you are met by dark, gloomy surroundings. A sense of dread fills the air. You feel a strange presence before noticing two featureless humanoid statues, standing motionless in the corner of the room.

A spiral stair leads down into this room. It is guarded by two Primordial Golems (see Cube General Features). They will not move to attack until an intruder steps onto the floor of the chamber. They fight until destroyed.

1 Square = 5 Feet#

B3: Chamber of Worms#

The floor of this chamber is filled with huge, writhing worms that wriggle and squirm over each other. The effect is quite disturbing. A narrow bridge crosses to the other side of the room, some five feet above the hideous, writhing worms. A featureless humanoid golem stands guard in the middle of the bridge.

The floor is covered with hundreds of juvenile purple worms. These are the Tarrasque’s food supply. Each of the purple worms has the statistics of a Giant Poisonous

Snake. If someone enters the pit, they will be attacked by 2d6 worms each round. The Primordial Golem (see Cube General Features) will try to knock intruders from the bridge into the vat of purple worms. The worms will not attack the primordial golem, because it doesn’t appear to be food. Area damage spells such as Fireball can kill most (but

not all) of the worms. Some worms will always survive, hidden beneath the corpses. No more than 5,000 XP can be earned here from slaughtering the worms.

B4: Breeding Chamber#

This must be some sort of breeding chamber for the worms. Two giant purple colored worms, more than thirty feet in length, are chained and entwined with one another in the center of the room. Featureless humanoid golems work on the worms, paying little attention to anything else in front of them.

This is the breeding chamber for the Tarrasque’s food. Purple worms breed in a manner similar to earth worms. The two Purple Worms join together and pass genetic material to one another. This is stored in sacs and then a cocoon forms on the body of each worm, with each cocoon holding 1d6 wormlings. Once these worm-filled cocoons are large enough, they are taken to the Chamber of Worms (area B3) and emptied. The purple worms here can also be milked for their poison.

The two adult purple worms in the room are restrained by adamantine chains. Three Primordial Golems (see Cube General Features) are currently collecting poison from one of the purple worms. They will, however, immediately stop work and attack any intruders. Even while restrained, the purple worms are not completely harmless. Anyone who comes within 10 feet of a worm’s head will be the target of a bite attack. Anyone who comes within 10 feet of the other end of the worm will be targeted by a stinger attack. Treat these as readied actions. Note that the purple worms will not attack the golems.

B5: Feeding Chute#

In this room, the walls and floors are covered in a thick, mucous slime that almost seems alive. The floor is marked by strange engravings that look like a grid. On opposite sides of the room are levers on the walls: one lever is shaped like a worm, while the other is horn-shaped. A shapeless humanoid figure stands in the chamber next to the worm-shaped lever.

This is where the purple worms are brought before being dumped on the Tarrasque as fodder. The worm-shaped lever on the wall releases a dozen small purple worms into this room. The other lever, shaped like a horn, opens a trap door in the floor, which dumps the worms into the Tarrasque’s chamber below.

One Primordial Golem (see Cube General Features) waits in the room. When the party reaches the room, the golem pulls the worm lever to dump a dozen purple wormlings (same statistics as Giant Poisonous Snakes) onto the floor. The golem then waits until someone enters the room. At this point, it will move to pull the other lever and open the trap door. Anyone standing on the trap door when it opens must make a DC 15 Dexterity saving throw or fall into the Tarrasque pit below.

B6: Dumping Hall#

This long hall has a strange floor. The floor appears to have dozens of small holes, each with an iron covering. At the far end of the hall, there is a circular metal door with a small lever located beside it.

This strange room is the mechanism for waking the Tarrasque. When the Tarrasque needs to be awakened, a primordial golem opens the circular door. When the circular door is opened, the entrance door slams shut and locks. This causes the hall to fill with purple worm venom in three rounds. The circular door automatically closes and locks after three rounds. All of the locks require a successful DC 20 Dexterity check using Thieves’ Tools to open. The lever beside the door can be used to open up the small holes in the floor. The poison drains through the holes onto the Tarrasque below and awakens the gargantuan beast. Anyone in the room when it is filling with poison will take 1d6 Poison damage per round.

Anyone who drinks or breathes in the poison (for example, with Water Breathing) takes the full damage from Purple Worm Poison or 42 (12d6) Poison damage. Anyone with fewer than 75% of their Hit Points remaining takes full damage from the second round onwards, as the poison seeps into their wounds.

B7: Poison Chamber#

This is where the purple worm poison is kept until it is needed. The Dumping Hall (area B6) describes the effects of being immersed in the poison.

B8: Chamber of the Guardian#

This chamber is dominated by an unearthly table with several goblets on it, each filled with a purple liquid. Sitting at the table is an insectoid humanoid with infernal features, and beside him are three bronze constructs that are designed with his likeness. The humanoid has a strange-looking talisman around its neck.

This room is where the caretaker of the prison, an Ice

Devil, can be found. Initially, he will not be hostile to the heroes. Instead, one of his Bronze Automatons (appendix B) will be used as a mouthpiece to communicate with the heroes. The ice devil is intelligent, and he understands why the heroes have broken into the prison. He seeks to be released from his bargain with Lutheria, so he is very open about his desire to assist the heroes. He is willing to tell the heroes how to awaken the

Tarrasque but, in return, they must swear an oath to kill

Lutheria and bring her crystal scythe back to him. This oath is a serious matter, and it will be enforced by the erinyes of the Island of the Oathbreakers. If the heroes are unwilling to swear the oath, then the ice devil expresses his profound disappointment in them. He attacks with the help of his three bronze automatons.

The strange goblets are filled with Purple Worm Poison. The ice devil has acquired a taste for the substance, and he is resistant to its effects. He won’t stop anyone from trying a drink for themselves, because he would find it amusing to watch. The bronze automatons are Sydon’s gifts to him; the Titan wished to curry favor with the ice devil in case he ever needed to use one of the weapons of the gods.

Treasure. The ice devil wears a Talisman of the Sphere around his neck. He uses this to control the Sphere of Annihilation in the Chamber of Execution (area B11).

B9: Golem Storage#

Featureless humanoid golems stand silent and still in a sad crowd at the center of this room. There are a dozen of them. Some have missing arms, while a couple have missing heads.

This is where damaged golems are repaired by the ice devil. None of them are operational, but the heroes don’t need to be told that they are broken. As far as the party is concerned, the golems are merely unresponsive.

B10: Locking Chamber#

This room is colder than the rest of the complex. There are four huge floating spheres marked by ancient runes. The walls are also covered in the same runes.

The Tarrasque can only be released from this room. Each of the floating spheres has an ancient legend about the Tarrasque inscribed on it in the Primordial tongue. All the stories are terrifying to anyone who can read them.

To open the cube, someone wearing the ice devil’s Talisman of the Sphere (area B8) must control the Sphere of Annihilation (area B11) so that it sits at the very center of the room. The wearer of the talisman must then read aloud the texts from each sphere. This causes them to spin. Once all of the spheres are spinning, the bottom of the cube will open, hundreds of feet below. The Tarrasque will be dumped into the Nether Sea, and the ancient beast will then make its way to the surface of Thylea and begin to wreak untold damage.

Releasing the Tarrasque. Releasing the Tarrasque at this point in the adventure is very unlikely. The ice devil is the only creature who knows the proper ritual, and he is unwilling to share this secret.

B11: Chamber of Execution#

A large, two-foot wide black sphere floats at the very center of this room. The sphere seems to absorb light.

The sphere at the center of the room is a Sphere of Annihilation. The sphere is part of the ritual required to open the Locking Chamber (area B10) and release the Tarrasque.

Killing the Tarrasque. The sphere also allows the ice devil to kill the Tarrasque if needed. The ice devil must move the sphere to the top of the sleeping Tarrasque’s head and then send it through the creature’s brain. If the Tarrasque is awake, this form of execution is no longer possible, as the Tarrasque will simply dodge out of the way of the sphere.

B12: The Pit#

A large pit looks down into a vast chamber that makes up most of the iron cube’s interior. Inside, a gargantuan nightmarish creature slumbers. A thick, spiny brown carapace covers the back of the immense reptile, which resembles a predatory lizard with clawed forelimbs slightly smaller than its legs. If the monster has eyes, they are not clearly visible from your current position.

The Tarrasque will remain sleeping unless it takes damage or it is fed with purple worms. If awakened, it will attack and attempt to consume anything in its pit.

If there is nothing to eat when it awakens, then the Tarrasque will angrily smash itself against the walls of its prison. The resulting noise echoes across the entire Nether Sea and attracts the attention of Lutheria. In this case, she will sail to investigate the prison in her throne ship, the Hypnos. Only after 24 hours of angry activity will the Tarrasque grow tired of battering itself against the walls of its prison and return to its slumber.