In This Life, The Greatest Star In The Universe - Chapter 304:

Kim Bo Myung, after graduating from high school years ago was living a below average life as an employee of an entertainment agencies PR department.After getting run over he opened his eyes to see that he was back in the past in the body of a member of an idol group?!He gets a chance to regain his lost dreams and write a new legend in the entertainment world and also get revenge !

When I woke up after a pretty crappy death, what greeted me was one of those famous fantasy worlds! I didn’t expect anything like becoming the strongest with a common job, or rising to the top with the weakest class…

This novel is also known as Female Star Student Is Awesome

Her best friend turned into her younger sister, destroyed her appearance, broke her legs, snatched her powerful fiancé, and designed to kill her mother. Unsatisfied, she locked her up in a mental asylum to be tortured until death!

Yun Hua returned to 13 years of age with hatred. This time, the debt of blood would be paid in blood.

Oppress the poisonous sister, beat up the scumbag fiancé, become the top student, become a scholarly expert, become a manhua artist. In the end, she became the chief anchorwoman on the largest global broadcast…

With one careless mistake, she accidentally took the gold medal during the Olympic swimming competition. The entire country cheered for the champion without knowing that she had no such intentions…

But all along the way, that unapproachable man protected her from nearby.

He spoke: For you, I would block deities. For you, I would fight gods. For you, I would kill Buddha!

He spoke again: If you don’t leave me, I won’t give you up either. I would rather turn my back on the world than slight my darling.

- Description from Novelupdates

Xiao Ran transmigrated to a fantasy world. As a dungeon guard in the Celestial Dungeon, with a special floor called the Purgatory meant for powerful demons and martial arts experts, he faced a huge challenge from the start. The Eldest Princess acquired a forbidden martial arts technique and was banished to the Purgatory. However, no one was powerful enough to restrain her. All the dungeon guards were defeated. Xiao Ran stepped up and declared, “Your Highness, it’s better for you to behave yourself on my territory” and effortlessly subdued the Eldest Princess.

He progressed from imprisoning the Eldest Princess to delivering the Great Xia Kingdom from the evil clutches of various demons and evil martial arts experts.

…

Xiao Ran was the mastermind behind the scenes.