MTL - Fairy: What Do You Call Borrowing Power? is This Unknown? - Chapter 826

The story is about a boy entering high school, who answers a strange call from a public phone one night. The caller challenges him to a bet: She’ll remove the birthmark which he sees as the cause of so many problems, and he’ll have fifty days to win the heart of a girl he’d considered far beyond his reach. And with this, a very strange summer begins.

What if life could be repeated?

But he became the clan uncle who was once called a lunatic?

Alas, wearing open-crotch pants in front of me, crawling on the ground, is it my two-year-old self?

I originally wanted to give my former self more New Year’s money, but I never thought that I would go from a braised pork stall to a food giant, from a small factory to an industrial empire.

- Description from novelbuddy

Year 2056, in a city in the Yuan Jiang Su Jin area. On top of a ruined, shattered six story residential apartment sits a teenager wearing a combat vest, militaristic trousers, and alloyed battle boots. On his back is a hexagonal shield and equipped is a blood-shadow battle knife. He sits there silently on the edge of the roof. At this time, the sparkling sky was shining and there was a refreshing breath within the air that blew towards him. However, there was only silence within the ruined, deserted city, with an occasional howl that makes your heart skip a beat.

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

- Description from Novelupdates