Kaos is the avatar of Pandemonius — the dark's own power made manifest, fashioned to defend it against creation. Where the Creators are the avatars of the light, made to bring creation about, Kaos is their opposite and their adversary: the keeper, whose purpose is not to make but to prevent, and to hold the dark in its unbroken stasis.
Two ancient figures stand behind it. The first is the chaos-monster — the primordial embodiment of disorder that creation must overcome, the dragon of the deep that the myths of the world set against the making of the ordered cosmos. The second is the guardian — the warden set to keep a threshold, who acts not to build but to bar the way. Kaos draws on both: the chaos that resists order, and the keeper that stands watch over it.
In the creation myths of the ancient world, order is almost never established without a battle. Scholars of comparative religion gave the recurring pattern a name — the Chaoskampf, the "chaos-struggle" — in which a god of order confronts and defeats a monstrous embodiment of primordial disorder, most often a serpent or dragon of the waters, and only then can the world be made. It is one of the most widely attested motifs in all of mythology, surfacing across the ancient Near East, in Greece, in the Norse world, and in the Hebrew scriptures alike.
Its fullest form is the Babylonian Enūma Eliš. There the primordial saltwater ocean is personified as Tiamat, a vast dragon of chaos, mother of the first gods, who turns against them and raises an army of monsters to unmake the order they represent. The young storm-god Marduk goes out to meet her; he catches her in a net, drives the winds into her body, looses an arrow that splits her, and from the two halves of her corpse he fashions the heavens and the earth. Creation, in this telling, is literally built out of the defeated body of chaos — the ordered world is chaos conquered and given form.
The same struggle echoes far beyond Babylon. The Canaanite storm-god Baal defeats Yam, the unruly sea; the Hittite storm-god slays the dragon Illuyanka; in Greece Zeus overcomes the monstrous Typhon, and in the Norse world Thor is set eternally against the world-serpent Jörmungandr. Even the Hebrew scriptures preserve echoes of the pattern in the LORD's defeat of the sea-dragons Rahab and Leviathan. In every case the meaning is the same: chaos is not a neutral emptiness but an opponent, a living force that the made world must defeat and hold back.