Because of love, reincarnation and rebirth.
They no longer remember each other.
Can they still complete "half of the agreement"?
Let's see how he turned the underworld, the ghost world, the demon world, the fairy world, the Buddhist world, the human world, the Shura world, etc. Upside down after reincarnation?
And where did he come from?
Can it change destiny?
And there is a huge conspiracy behind it.
This is what is called 'fate'