MTL - Illimitable Until Death - ~ 150 very serious problem

He rose from hardship, but was felled by betrayal. From then on, one man, one gun; treads the path between Evernight and Daybreak to became a legend. No matter what was destined to be his fate, he intends to become the ruler who dictates.

Su Wan is a Realm Destroyer. She shuttles to different time-spaces using the identity of the “Cannon Fodder Ex-Girlfriend”, dedicated to plotting how to happily tear apart the male protagonist and the female protagonist. –There’s no such thing as protagonists who can’t be torn apart, only Ex-Girlfriends who don’t work hard enough~

- Description from Novelupdates

The story is about a boy entering high school, who answers a strange call from a public phone one night. The caller challenges him to a bet: She’ll remove the birthmark which he sees as the cause of so many problems, and he’ll have fifty days to win the heart of a girl he’d considered far beyond his reach. And with this, a very strange summer begins.

Zhong Yuhuan had transmigrated into a book and became the female supporting character who was destined to die an untimely and tragic death. Coincidentally, her family adopted two boys — the male lead and the villain of the book!

The male lead of the book would become a superstar in the show business and the villain a super successful and powerful businessman.

Zhong Yuhuan thus began her life of raising the male lead and the villain while faceslapping other scums. She would grow up quickly and live the life of the rich and powerful Mary Sue!

- Description from Novelupdates