Bullying

Good grades, a handsome appearance, above-average fighting skills, and a little bit of righteousness. On the eve of his graduation, Kim Hyun-sung gets pushed off a rooftop ends up in a vegetative state. Unable to die, with only his hearing and consciousness alive, he spends the next ten years in hell until he suddenly returns to the day the bullying began.
?? ??, Evil school, School of Evil
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Bullied mc makes a deal and sells his soul to the devil to acquire some power and get revenge on bullies
At some point it got kinda confusing but the beginning was goood

revenge on bullies who raped his best friend

Yu Ijin was the sole survivor of a plane crash when he was little. After becoming a mercenary to survive for 10 years, he returns to his family in his hometown

Jeongmin is a loner in high school being bullied by the Queen Bee, Juhyeon. The two were friends in elementary school before their friendship ended because of Juhyeon’s demand that Jeongmin should only be friends with her. Juhyeon uses this “betrayal” to fuel the classmates' insults and isolate Jeongmin in misery. Jeongmin has only one way to escape, through lucid dreams. One day, a mysterious man enters her dreams and offers to help her get revenge on Juhyeon…