The Demonic Twelve mythos. Creation.

The Givers do not see each other as siblings so the constant fights and their mating with one another is much more understandable.
After each world creation Life and Death fought to see if the planet would have living things, Death won every time until feeling sorry for Life, Heat made the others create one planet for each Giver to do with as they please. Death didn't like how Heat was taking pity on his rival and challenged him with, to everyones surprise Heat as victor. The Givers made one last world to be inhabited by their children. After they came together to make this perfect world. Death was still sore about his defeat so after the perfect world was created he traped Heat within the stars and fought Life for full control over the universe. Cold opposed but was quickly silenced by Death. during the battle he violently raped Life impregnating her. Life with power from her unborn children defeated Death and seal him deep in the planet. The givers freed Heat and their 12 children then lived on the planet.