Reincarnation: I Married My Ex’s Brother - Chapter 1199

A teenager who unexpectedly gets transported to the modern world from ‘the world of the immortals’ . He finds himself in the body of an ordinary guy. He wants to go back to his world and for that, he will have to practice to get stronger and investigate the reason why and how he crossed through to this world.

- Description from Novelupdates

[*Ding*

Gray was just a normal guy. No powers. No family. No future.In a world where strength and status decide everything, he was at the bottom.He worked hard just to survive, taking care of his little sister after their parents were gone.But no matter how hard he tried, life never gave him a break.And after losing his only job, Gray was ready to give up completely.Then something strange happened.Just as about he was to end his life, an unknown voice echoed in his ears.[Welcome to the Great Tycoon System.]And for the first time, Gray had a way to fight back.From being weak and broke, he’ll rise to the top—one coin and one job at a time.Because in the world where money can buy power, Gray is about to become the richest and strongest man alive.

I fell into a game world out of nowhere with an instant kill skill.
And then somehow, I became a bigshot.