Even If I'm Reborn as a Cute Dragon Girl, I Will Still Make a Harem - Chapter 216Book 5: : Old Wang

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

My whole life, all I wanted was power.

I churned the world into rivers of blood and eventually gained the title, “Demon Lord of Strength”. However, all this became useless when I lost to a party of heroes.

But what can a loser say? As I laid dying, I was forced to listen to the hero’s gibberish:

“If you are born again, I hope that you will live a kind life!”

But huh? When I opened my eyes again, I was back in the past.

“What do I have to do to live a kind life?”

This is the beginning of an ex-Demon Lord’s journey to live a kind

Roy’s life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
…
It’s really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!

drop out of school

When I got home, I reopened the blacksmith shop.

From then on, this blacksmith shop was no longer ordinary.

The best knives in the world are born here.

The thrust-to-weight ratio of the handmade micro-turbojet directly exploded.

The micro-drones flourished in his hands.

- Description from novelbuddy