Limbo is a plane of pure chaos, a roiling soup of impermanent matter and energy. Stone melts into water that freezes into metal, then turns into diamond that burns up into smoke that becomes snow, and on and on in an endless, unpredictable process of change. Fragments of more ordinary landscapes—bits of forest, meadow, ruined castles, and even burbling streams—drift through the disorder. The whole plane is a nightmarish riot.
Limbo has no gravity, so creatures visiting the plane float in place. A creature can move up to its Speed in any direction by merely thinking of the desired direction of travel.
Limbo has no layers—or if it does, the layers continually merge and part, each is as chaotic as the next, and distinguishing one from another is impossible.
Limbo conforms to the will of the creatures inhabiting it. Creative imaginations can create whole islands of their own invention within the plane, sometimes maintaining those places for years. A nonsapient creature such as a fish, though, might have less than a minute before the pocket of water surrounding it freezes, vanishes, or turns to glass. Slaadi live here and swim amid this chaos, creating nothing, whereas githzerai build entire monasteries with their minds.
As a Magic action, a creature in Limbo can make an Intelligence check to mentally move an object within 30 feet of itself that is on the plane and isn’t being worn or carried. The DC depends on the object’s size: DC 5 for Tiny, DC 10 for Small, DC 15 for Medium, DC 20 for Large, and DC 25 for Huge or larger. On a successful check, the creature moves the object 5 feet plus a number of a feet equal to how much the total exceeded the DC.
A creature can also take a Magic action to make an Intelligence check to alter a nonmagical object within 30 feet of itself that isn’t being worn or carried. The DC is based on the object’s size: DC 10 for Tiny, DC 15 for Small, DC 20 for Medium, and DC 25 for Large or larger. On a successful check, the creature changes the object into another nonliving form of the same size, such as turning a boulder into a ball of fire.
Finally, a creature in Limbo can take a Magic action to make a DC 20 Intelligence check to stabilize an area within a 30-foot-radius Sphere centered on a point it can see on the plane. On a successful check, the creature prevents the area from being altered by the plane for 24 hours or until the creature takes this Magic action again.
Limbo is change. That constant churn is most easily discerned in the ever-shifting physical form of elements altering and reconfiguring in the vast expanse of the plane, but it applies just as much on a mental and emotional level. Visitors to the plane find themselves caught up in a storm of intrusive thoughts and unruly emotions, forcing them to confront the transient nature of so much of what they think of as their identity. The key to success on this plane—both in shaping the physical environment and in mastering the internal landscape of chaos—is asserting one’s sense of self, identifying what is unchanging amid the storm of constant change.
The sanctuaries of the githzerai are among the few havens that adventurers can hope to find on this tumultuous plane. Although githzerai aren’t generally hostile to visitors who come in peace, they don’t welcome those who bring the chaos of Limbo with them: a tumultuous heart brought into a refuge can unravel the entire sanctuary.
Adventurers might also come to Limbo to explore the secrets of the Spawning Stone. Said to have been created by Primus, the overlord of the modrons, the Spawning Stone absorbs chaotic energy and makes it possible to shape enclaves of order in Limbo, but the chaotic energy it absorbs is responsible for the creation of slaadi.