A Villain's Guide to Saving the World - Chapter 31: The Great Villain! Thrust Into Yet Another Threefold Battle...?

What would happen, if one day fantasy collides with reality?

- Description from Novelupdates

After his qi center is destroyed, a martial arts instructor of the Blood Demon Cult is assigned to learn and research the martial arts of four captured murim masters. However, when the Cult betrays him and decides to kill him, he fights back and everyone in the Cult dies, including himself.He then mysteriously wakes up in the body of Baek Suryong, a young martial arts instructor in the rural countryside with a disease that will kill him within three years. He realizes that the martial arts he had learned holds the key to healing his new body’s illness, but in order to do that, he needed money. A LOT of money.Baek Suryong thus embarks on a journey to become the Star Instructor of the Azure Dragon Martial Arts Academy, and earn enough money to save his own life! Perhaps he would even manage to educate some kids along the way…

It was only after Su Yayan's death that she realized that she was a malicious cannon fodder female character who became a scapegoat in a Mary Sue story.