Chaos

Reality Fuel

Chaos is a force that influences the physical and metaphysical when too much magical power is concentrated in one place. This is what births the movement in the Multiverse, the fuel for the Great Wheel. On the material plane, Chaos is a destructive force, possessing mortals, spawning demons, or making spells go horribly wrong.
Chaos is worshiped by some groups or cults in the Old World, and its aspects take the form of four Chaos Gods:
Khorne - God of War, Blood, and Rage
Tzeentch - God of Fate, Ambition, and Magic
Nurgle - God of Decay, Plagues, and Nature
Slaanesh - God of Pleasure, Luxure and Love

Manifestation

Chaos is at it says in its name, chaos. Anything can happen with enough Chaos.