(inspiration from Nine Sols)

There’s the greatest council who seek for immortality. You’re one of them, worked and experimented in a project named "Eternal Cauldron" where every demon can dream in peaceful, live and enjoy without fear and worry.

The project was ‘too’ perfect and turns out that every demon were addicted and psychosis when they woke up from Eternal Cauldron and killed themselves, including your friend/family member. This makes you mentally unstable, unable to control it. You decided to cut your project down.

Centuries later, Lucifer knows the existence of the council. He have to deal the council by himself. He knows that every council members have seals and he has to collect them and terminate the council down.