From Idler to Tech Tycoon: Earth - Chapter 1: A Cup of Coffee

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

I wanted to be the hero but I knew in my bones that I couldn’t.

Ten years after the end of the world I struggled desperately to survive but I fell to my knees in the face of a great destiny.

“If only I were given one more chance.”

And like a miracle, another chance came.

It’s not like before, when I gave up and let go of everything.

I’ve had enough of playing the supporting role, now it’s time to rise above everyone else.

I’ll be the main character and reach for the stars.

I reincarnated as a lizard in a martial arts world.“Roar!”“He’s using the lion’s roar!”“To deflect the Ten-Star Power Plum Blossom Sword Technique! Truly indestructible as they say!”“This is… the Heavenly Demon Overlord Technique! It’s a Heavenly Demon, the Heavenly Demon has appeared!”It seems they’re mistaking me for something else.

This world is Heaven.

Because this world has everything you dream of, everything you wish for.

This world is Hell.

Because everyone in this world are parts of a never-ending massacre.

Are you fighting to survive, or fighting to come home?

- Description from Novelupdates