One Piece: King of the World - Chapter 6 - : Lunch with Zephyr

Takebayashi Ryouma, a 39 years old man with hidden past, found himself in a strange white room. The gods tell him that he has died and that they are sending his soul to a different world, a world where magic exists. After living alone for 3 years, his gamer soul loses its common sense and starts along crazy routes.

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

After seeking pleasure in the nightclub and a night of romance, he discovered there’s a seed in his stomach;

He was the hunting hound of the Baskerville family.

But at the end, he was branded as a traitor and executed.

— — —

Now, he has returned… after 40 years.

“This time, they will be my prey… and I’ll bite every single one of them to death!”