Trillion is the central antagonist in Trillion: God of Destruction.
It is an aggregation of a trillion curses, with an instinct to consume the deepest parts of the three realms. It swells in size by consuming the Core of each world. The Underworld has come to know this monstrosity as “Trillion.” It is a horrifying entity that nearly plunged the Underworld into complete annihilation during the first Great Overlord’s reign. In the gameplay, it literally has over 1 trillion HP life, and when it attacks, the whole map goes red, indicating its attack.
As revealed in the true ending, Trillion was originally the Overlord of Gluttoney from another dimension. For reasons that are not entirely clear, she killed the Great Overlord whom had promised they would "be together forever." She blamed the outcome on God and ate him, body and soul. She consumed the cores of Heaven and the Underworld, and turned into a monster.
With neither it's hunger nor anguish sated, Trillion began traveling between dimensions so it could devoure the heavens and the Underworld over and over again.
Trillion is shown to be jealous and vengeful, extending it's hatred for God to most any being that tries to resist it. It seems to take a perverse pleasure in torturing the overlords it defeats by consuming them bit by bit.
In it's first form, Trillion has the appearance of a white, gigantic, colossal skeleton-like dragonic beast with large claws and a large mouth on its lower half. Considered by the Underworld as "The Evil God that Consumes All"
Faust describes the second form as being better suited for combat. It takes the shape of an immense winged dragon. It has a second mouth on it's belly in a similar fashion to the first form, a core of pulsating energy can be seen on it's chest and two ball-like entities with gnashing teeth float beside it in combat. They are not classed as part of Trillion's body for the purposes of the part-seal death skill, but are referred to as "hands" ingame.
Trillion's final form is supposedly it's "most natural" state, by Faust's conjecture. It is much more humanoid than the previous forms, though it retains a set of wings and horns. It has long hair, a mouth that makes up the lower half of it's body and wields an oversized knife and fork.