It sat on a throne of infinite blackness, in a castle where walls of bone were bound together with blood. The long black hood covered a mostly wizened face, pale as the moon, and jagged yellow teeth were always bared, ready to shred flesh if needed.
Nothing else lived with it. Nothing else could. It did not breathe, so there was no air. It did not eat, so there was no food. There was only the castle walls, and the throne.
Sometimes, the throne would flicker with light, crackling like lightening despite the darkness. The light was more than it appeared - it was a sign, a symbol, that what it needed - what it craved - more than anything else, was happening.
Across more worlds, more galaxies, more dimensions than anyone could ever count, it could feel war, and suffering, and pain and rage. Not only could it feel them, it absorbed them. It didn't really love them - it felt satisfied by them, the way a person felt satisfied after a good meal.
And when conflict waned, and it could feel its power drain, like a spider could feel its web tingle, it would send forth its own essence, beings of its own creation, to go forth, and breed war.
No one knew its true name, for it did not have one. No one could really know if it existed, but across the planes of existence, people spoke of different creatures, dark, twisted and evil - that swept into a land and left death in its wake. And there was nothing, nothing, anyone could do to stop it...
But there was one who fed its hate more than anything else. One who had been borne out of its desire for war before it had found another way. One who offered a form of companionship - until she had betrayed it. It lived for war - but it had special plans for her...