Sometimes when a creature dies, its spirit refuses to part with the last purpose it had given itself in life. If the desire and will of a psyche is strong enough to outlast its bodies last breath, it can manifest itself in a destilled and pure form of this last intention.

These spirits will then venture on, caught in the fabric of their very own existence- They can decide to fight against their last intentions, or they can chose to obey.

Tiangou is one of these beings.
His will was to destroy the one being that caused his madness when he lived. But it was not another being he intendet to destroy- he killed himself. In bloodrage and mad desperation, after realizing he was the single cause for the mistakes he did, the horrors he witnessed and the evil he started- he lost his conciousness in his own madness and ripped himself open in a frenzy.
The will carried on, but he changed.
When he found himself being rather far from death, he noticed that his hatred was gone, as was his former body and self.
He became something terrifyingly pure and more destructive than before. He came to accept that his fate would carry on into this new existence. Only this time, stripped from his bloodlust and blindness, he had a mind sharper than ever before and he knew what this new forms purpose would be.

To cast darkness upon those, who cast darkness upon themselves.