After Marrying a Vegetative Princess, I Went Crazy With Joy! - Chapter 229:

In a world where power defines worth and survival is a privilege earned through strength, Ronan was just another broken soul—bullied, beaten, and forgotten.Until he snapped.[System Activated][You have acquired an S-Class Ability: Starflame][Extreme rage and deep-seated hatred detected][You have obtained the unique skill: Devil’s Covenant]Once a victim, Ronan begins to rise—with a system by his side that grants him power through every action.When he cooks:[Skill Acquired: Home Cook]When he reads:[Skill Acquired: Speed Reading]When he fights:[Skill Acquired: Vital Strike]And these skills?They evolve.[Skill Devil's Covenant has upgraded into Devil's Divine Judgement][Skill Speed Reading has upgraded into Hyper Comprehension][Skill Energy Slash has upgraded into Demonic Slash]Every moment, every breath, every choice brings him closer to power.A hero, or a villain?He stands among them.

What would happen when someone from our world was suddenly reborn into the world of My Hero Academia with a Gacha System that rewards him with abilities, techniques, and skills from Jujutsu Kaisen? Grand epic fights and crazy shenanigans as he goes through the story to cause chaos and change the world to his liking.

Cale Virel was just a normal office worker.He was bored and tired of his life, waiting for it to end.And then—Bam!One night, two robbers targeted him!And instead of surrendering, he fought back!Though, in the middle of doing so—PHUCK!He got stabbed and died...He didn't regret it though.After all, he's not really afraid of death anymore.And so...He rested in peace..........Or so he thought!Cale Virel—“Huh? What the fuck?”He woke up as a young slave named Kaiser in a different world!And given another life he didn't ask for again—“Fuck this shit!”Cale, or should I say—Kaiser—“Ugh, whatever.”Decided to live it... By just doing whatever he feels like until he dies.

Su Ran, a music prodigy, woke up transmigrated into a book.

At that point in time, the main story arc in the book had already been completed. As a villainess female supporting character, not only did she need to take over the original owner’s pitiful life in poverty, she also gained an instant son right at his rebellious period.

Ten or so more years from then, the son would turn into a twisted, evil villain. He would appear in one of the extra chapters to pick on the male and female lead’s children.

***

Su Ran: Son, you shouldn’t be too outstanding.
Su Han: Why not?
Su Ran: ’cause you will be killed.

Su Ran: Son, would you like to learn music from me and become a zen, little fairy boy who only needs to drink dew.
Su Han: No, I want to go into business so I can support you.

- Description from Novelupdates