- It is a plane of exile.
- It is the prison plane of the multiverse.
- It is where the overthrown plot their return.
Carceri seems the least overtly dangerous of the lower planes, but that first impression quickly disappears. Acid seas and sulfurous atmospheres may be rare on this plane, and there are no areas of biting cold or infernos of raging heat. The danger of Carceri is a subtler thing. The plane is a place of darkness and despair, of passions and poisons, and of kingdom-shattering betrayals. On Carceri, hatreds run like a deep, slowmoving river. And there's no telling what the flood of treachery is going to consume next. It is said that a prisoner on Carceri may only escape when she has become stronger than whatever imprisoned her there. That's a difficult task on a plane whose very nature breeds despair, betrayal, and self-hatred. Unlike most inhabitants of Carceri, the deity Nerull makes his home on Carceri willfully, not because of exile. Carceri consists of six layers. Each layer has a series of orbs like tiny planets, in a row. A gulf of air separates each orb from the next. On a particular layer, little distinguishes one orb from the next, and it's possible that the number of orblike planets on each layer is infinite.
- Normal Gravity: On the orbs, gravity is exactly like the Material Plane. Between orbs, there is no gravity, which eases travel for those who can fly beyond the clutches of each orb's gravity.
- Normal Time.
- Infinite Size: Carceri may extend infinitely, but it possesses finite components in the form of its tiny planets.
- Divinely Morphic: Nerull and any other entity of lesser deity power or greater can alter Carceri. More ordinary creatures find Carceri indistinguishable from the Material Plane; it responds to spells and physical effort normally.
- No Elemental or Energy Traits.
- Mildly Evil-Aligned: Good characters on Carceri suffer a –2 penalty on all Charisma-based checks.
- Normal Magic.
Portals on many planes allow travel onto Carceri. But almost none allow access in the other direction. One exception is the River Styx, which runs through the first layer of Carceri, mixing with the bogs and canals that crisscross the orbs of this layer, on its way to the Gray Waste of Hades.
Almost no creatures live on Carceri voluntarily. The exiled, the shunned, and the defeated are sent here, as are traitors, backstabbers, and the souls of those with underhanded ambition. It's the prison plane, pure and simple. Carceri's residents are thus a mixed bag, racially and culturally. Most continually plot and scheme to leave Carceri and find their way back to their homes and former positions. Besides prisoners and petitioners, Carceri hosts fiends that partake in the endless Blood War. Demons, devils, and yugolorhs all roam Carceri, as do madly galloping nightmares and other evil outsiders.
Even if they wanted to, Carceri's petitioners couldn't leave, so they hold a powerful resentment for visitors merely passing through. Most petitioners on Carceri are souls who abused trust and betrayed friends or family. Like all petitioners, they have no memory of their past lives, but they remain treacherous. They lie—constantly, compulsively, and with great cunning. Petitioners on Carceri reside on one of five layers according to their particular treachery. Orthrys holds politicians and national traitors, and Cathrys holds those who gave in to animal lusts when logic and reason would have served better. Minethys imprisons hoarders who could have helped others with their wealth but didn't, and Colothys confines liars whose untruths harmed others. Finally, Porphatys is home to the shallow and selfabsorbed who refused to aid others when the opportunity presented itself. Carceri's petitioners have the following special petitioner qualities:
- Additional Immunities: Cold, acid.
- Resistances: Electricity 20, fire 20.
- Other Special Qualities: Petitioners on Carceri lie often and well, receiving a +10 competence bonus on Bluff checks.
Movement and Combat
For characters on an orb of Carceri, movement functions normally. Once a character gets more than 100 feet off the surface of an orb, gravity disappears. But unlike other planes with the no gravity trait, force of will doesn't provide a means of locomotion. Characters need a fly spell or another means of movement to reach a different orb. Carceri's natives sometimes use ferrous sleds that slide through the air as if it were solid, skin balloons filled with hot air, and spinnerets whose 1oo-foot silk lengths catch the wind and pull a traveler off a high mountain to a random destination. Certain channels of the Styx and well-hidden proper portals allow movement between Carceri's layers. Combat on Carceri functions like it does on the Material Plane.
Carceri is called the sixfold realm because it has six layers nested within each other like little wooden dolls. On each layer, a strand of small planets stretches in two directions toward infinity. Many of Carceri's layers are battle-scarred and wasted, the legacy of the Blood War. While much of Carceri remains oblivious to the war raging across the lower planes, portions of Carceri are used as staging grounds and even battlefields. Vision is normal on Carceri. Unlike on the Material Plane, natural light seems to seep upward from each orb, bathing everything in a reddish light. Hearing is normal on Carceri.