Returning to the Mysterious Era - Chapter 400 - Ill Use Your Life As Compensation

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

Shen Yaowei was an idiot her entire life, and was finally sent to death by the person she trusted the most. After being reborn, Shen Yaowei was no longer silly. She just wanted to cling to the future tyrant and live a life of luxury. Possessing almighty skills and being known as a foolish girl, Shen Yaowei pretended to be an idiot and went on a killing spree, abusing the scumbag until he cried for his mommy and daddy. Anyone who stopped her from clinging onto the tyrant would have to die. Soon, everyone discovered that the frightening Prince Li, who had always been a loner, had changed. There was always a small shadow following behind him. “Ninth Uncle… I don’t have the strength to walk. I want you to carry me…”

the little shadow spread her arms towards His Highness, looking pitiful. “Yaoyao, I’m strong so I’ll carry you!” her elder brother, leader of the martial arts alliance, arrived at the battlefield instantly. “No, I’m stronger! I’ll do it!” her second brother, a miracle doctor, came forward. Then her third brother, fourth brother, fifth brother… All the bigshots had arrived, asking for hugs and to let them carry her. “All of you, get lost! That’s my darling daughter, so I’ll carry her!” Her father, a great general protecting the country, rushed as fast as possible to Shao Yaowei’s front, only to find that the aloof, noble and peerless prince had already knelt with his back facing Shao Yaowei. “Come on, Yaoyao. I’ll carry you.”

When the system warned the world that it was coming a week in advance, Alex couldn’t have been more excited. In college for a degree he didn’t care about to get a job he didn’t want, the promise of a world where magic and challenge awaited — even at the potential cost of death — was the best news he possibly could have imagined. Alex was ready for a new life. He ready for his only friend to shove him through a portal into hell the moment the apocalypse started. Instead of getting to punt rabbits and farm wolves, Alex finds himself stranded in a warped world where even the bugs are stronger than he is. Even with a summoner class that gains the powers of its monsters, most people would have died. Alex didn’t get the memo. He might have liked challenge a little bit too much. Where others saw certain death, he found something else. Opportunity.