After Rebirth, the Miracle Doctor Wife Is No Longer Humble! - Chapter 15: Rules

An ordinary student, a wretched peeper, a cowardly teenager with a kind heart. In a terrorist attack, he inherited the knowledge of countless elites, embarked on a path of God Jagged Tu…

He is an artist!

He is a mathematician!

He is a psychology Doctor!

He is a master of fighting!

In fact, he is a man

Taken off raw site:

A wretched, dirty young man is working during the summer when he was caught up in a mysterious explosion. After that explosion, the young man is then left with the memories and knowledge of dozens of the world’s experts.

He has changed, his heart has become cold, iron-blooded. He became a killing machine, his mind turned mechanical, calculative. Everything goes according to his plans and calculations!

In this magical, slaughterous world, a door is opened for him…

- Description from Novelupdates

The Hero’s party was attacked by a large group of powerful devils. The party will no doubt be annihilated if this were to go on.

I never thought I could become a hunter.I never thought I would get the chance.But that wasn’t true.「 ‘Tower of Trials’ has selected all suitable candidates from Earth. 」「 Please select your difficulty. 」「The chosen difficulty will be directly proportional to your rewards. 」I was given a chance now.A special one at that.

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…

- Description from Novelupdates