Ülgen is the luminous creator-god of the upper world, architect of the cosmos and giver of fire and life to humankind, dwelling above the layered heavens. In Khakas belief he and his brother Erlik together shape the land, vegetation, mountains and waters, their light and dark natures holding the world in equilibrium rather than open war. Sources differ on whether Ülgen and the supreme god Khudai are separate deities or two names for the same creator, the two being invoked side by side in shaman prayers.