In the demon world, an abyssal demon is born every 100,000 years, and its power is enough to stop the gods.
The Power of the Universe says: I am fair.
Therefore, the Abyss Demon must exchange his life for power. This is what is called 'fairness'.
Cosmic Power says: Do you want to live?
Go to another world to find the 'designated person', find him/her, and sign a master-servant contract with him/her, and you will survive.
"Beat, if I die, will you shed tears for me?"
"... No." I won't let you die, otherwise I won't be far away from death.
"Why?"
"Because I am a devil." Because I am a devil, my blood is cold. Devils don't need emotions.