In DC/Young Justice with the Omnitrix/Ultimatrix and a Chat Group - Chapter 30: Connection

As a child with an unattainable dream, I yearned to become a Hero, but I veered off the right path. Looking back, my aspiration to save others was nothing more than a foolish dream. I now realize the magnitude of my sins and the impossibility of atoning for them.

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

Calling the old god’s mage, the knight who inherits the bloodline, looking forward to the glory of yesterday;

The noise of steam engines and the roar of cannons indicate the direction of the future;

An Sen, who was living in this world, embarked on a road that had never been imagined;

In the ashes of the old world…he shall be crowned king!

- Description from novelbuddy

In the back of the forest lives Allen, the antisocial wizard. He is feared by the people around him and called the “Demon Lord”.One day, while living out his life as a hermit, he finds a young girl named Charlotte who collapsed. Although innocent, she was accused of evil wrongdoings, had her engagement broken and was forced to flee her country.Upon hearing that, Allen recalled the bitter experience of being betrayed by a party he once believed to be his companions. Hearing the story of the 17 year old’s exploitation, Allen decides, “I’ll let her live in my mansion, and I’ll teach her all sorts of bad things…”