Chaos

Chaos is the primordial, supreme darkness, and the sworn enemy of God.

Pre-Creation
Prior to Genesis, Chaos reigned supreme in this nothingness. During this time Chaos gave birth to several terrifying creatures. The Elemental Demons- Leviathan, Behemoth, Ziz, and Surt. The Four Horsemen of the Apocalypse, capable of bringing the end to any world.

Defeat and Imprisonment
Though Chaos' reign wouldn't be infinite. When creation began, Chaos was dissipated. However, it would be used as a force of good, in which all life on Earth would live in peace with each other (i.e. a lion and a zebra sleeping together).

Unfortunately, this harmony wouldn't last forever. When one of the archangels rebelled against God, humanity was corrupted. By sinning, Chaos was turned into a force of evil, and thus evil came to the world. To prevent Chaos from destroying the world, God imprisoned Chaos in

Personality
Chaos appears to be an amoral being, who seemingly can't tell the difference between good or bad. It is implied to act purely on instincts, and feeds on creation in order to survive. It seems to know only destruction as this appears to be the sole purpose of its existence. However, its actions can be influenced by someone more powerful than itself or something akin to it. For example, God was able to bend Chaos to His will and so there existed "good chaos." Through sinning, humans have twisted Chaos, turning it into a force of evil.

Interestingly enough, not everyone considers Chaos an evil force. Lucifer pointed out that God imprisoning said being was an act of injustice, although in order for creation to exist, Chaos must be contained and balanced. In truth, Chaos' moral alignment depends on those who are around it.

Appearance
Being the personification of nothingness, Chaos takes the form of complete, infinite darkness. It is a cold and unpleasant force, capable of infecting those it touches, giving them "Chaos Rage", the way it sees the world.