Leviathan's true origin is unknown, though given its many millennia of existence and rule over the Cenobites and Hell, some believe that it is possibly the fallen angel from the Bible. It looks like a solved Lament Configuration, and reshapes into a cube when its powers shut down. It has also been shown in human form in order to give The Box to those who can solve it, as well as a dragon that reclaims The Box while on Earth.
Leviathan is obsessed with law and order, and views the human realm of flesh as chaotic and wrong. It uses the Cenobites as its foot soldiers in the war against chaos and flesh. The Labyrinth which it presides over represents the maze of the mind.
Powers & Abilities
Leviathan is immortal and has the power to create any Cenobite in any way, shape, or form as it sees fit in order to serve it. It emits beams of black light that causes those hit by them to see and feel their sins and wrongdoings. It feeds on the souls of those that are brought to Hell, but are deemed unworthy to become Cenobites.
Leviathan gets weakened however and suffers a temporary power loss when the Lament Configuration is solved while in Hell. When this happens, it reverts into its cube shape and its captured souls flee out of it at a rapid rate.