Eternal Collapse

Eternal Collapse is a very powerful high-grade Curse Magic spell, which has never been seen used by anyone, but it is rumored that only were powerful mages can do this, while no records of any grade of this specific type of Curse Magic existing. This spell is what caused the original Demon Emperor to crumble, said to have been cast by a very powerful mage who disapproved of the global climate 4000 years ago.

Usage
Eternal Collapse is a part of the Curse Magic series, one of the more shrouded ones with no clear incantation or note of. Its usage is very clear, when casted it is attached to a target permanently and a certain timestamp is set for when the collapse will go off. It was first used against the original Demon Emperor, who succumbed and his soul was split after a thousand years. This also split his total energy levels and magic capacity in half each time his new souls were split apart. There has been no way to undo this, even with the Obsidian Knife, suggesting that this type of magic is outside of the level cap. There is a way, however, to avoid it from destroying your soul, as the current soul inheritors of the original Demon Emperor seem to sacrifice exactly a thousand souls to live a thousand more years.