Magika no Kenshi to Shoukan Maou - 2.5.2 — The Qualification of the Living

Shi Jin once read a book. It was supposed to be about satisfying the desire for vengeance.

An Apocalypse descends—as a lethal super-virus wipes out most of the human population. It took less than a day for the world to change forever—bringing mankind to its knees.It’s a time of misery and death for most, however, there are some who are lucky. Zane Graves, who came across a “Blood Crystal” is given an ability: [Dead Man Walking]—which grants him a special power, and so setting him off on his path to the top!

Doomsday comes, and human beings enter the heavenly world.
Ten years later, Yang Chen, who was betrayed tragically, returned strongly with the Tianyu bug. In this life, he vowed to make the betrayal pay the price. He has a powerful bug bonus, just like an open hang. Frightened to hear…

- Description from novelbuddy

MC (female protagonist) dies in a plane crash and wakes up in the body of a beautiful but corrupt and lascivious prime minister in ancient times, Zhang Qinglian. As circumstances decree, he (she) cannot reveal that the original owner’s soul is gone else calamity might occur. So he (she) decides to walk a righteous path, determined to help the lovely but simple little emperor rule the country. Not backing down after facing torture, not losing courage, destroying rebellions and facing off with scheming princes.

- Description from Novelupdates