What?! My Boss, the Ghost King, Is My Ex

[Not mutually exclusive purity, strong female lead, underworld agents, metaphysics, ghosts and monsters]

A test subject whose life is controlled by others will always meet the same end, no matter how much they try to change it.

Bai Fengjiao did everything she could to save Fu Yu's life, even wagering her own life and livelihood.

Fu Yu was reincarnated as a girl, Shi Meng, and forgot her past. When she learned the truth, Shi Meng couldn't accept reality. The pressure she suffered day after day drove her to become a villain.

Wangyou watched helplessly as the reincarnated Fu Yu became a great villain and tried to destroy everything. Unable to bring herself to destroy him completely, Bai Fengjiao sealed him away in the Nether Abyss, but paid for it by losing the chance to become an immortal.