The Gate Traveler - Side Story 12: A Call for Help

I’ve become a rogue lord in another world! This is the story of a game I was playing! The story of the protagonist, who has become a rogue lord who dies after two days, successfully uses the game’s history and system to escape his impending doom and become the strongest.

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.

Chen Mobai, a third-year student of Xianmen No. 5 High School, is working hard to review and prepare for the entrance to Daoyuan. The direction of his efforts is: to develop a new world

- Description from novelbuddy

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!