Valerian, The Legendary - Chapter 271 - 271 Reaching For The Roots.

Before going to college, an ordinary high school student went to celebrate and got drunk. When he woke up, he found himself in a completely different world. There was a big sect, the approaching sect entrance examination, a slum where his body’s previous owner lived, and a shared memory about a missing young girl.

When he got tangled in a fight with a few punks in this different world, he fell off a cliff and miraculously found himself still alive, with two more voices ringing inside his head. They were Sword Master and Saber Master. In the company of them, he continued to find out more about this whole new world. He took the sect entrance examination, entered the sect, met a strange man in black, and even participated in a major competition of the sect to have a chance to win over his peers!
In this whole new world, he was born again and got to explore the fantastic martial world!

- Description from Novelupdates

The old man pointed to the flower-like woman and said, “Call her mother from now on.” He then pointed to a flower-bud-like girl and said, “This is your sister.”

My younger sister was not cute.

She was arrogant, taciturn and weird, but she knew how to please our parents.

She was two-faced and deceitful, but it seemed like she only treated me that way.

I cared for her, tried to please her as much as I can, but she still disliked me.

Until one day, I found out her secret, our relationship began to get a little bit weird…

Seo Tae Hyuk, jailed after being falsely accused.

A young man with an extraordinary mind is off on an exciting adventure when he mysteriously wakes up in the body of a feeble slave-guy in a different, rich in quirks world.

The main character, a selfish jerk, would use extreme means to achieve his goals. However, he never allows his base instincts to overrule his sense of decency. He always pays back both good and bad deeds.

Will his (terrible/excellent) mentality help him make a fresh start? Will he get through misfortunes and hardships of the new world?