Marvel: Empire of Power - Chapter 59: The Birth of a Star-Spangled Man, A Shadow’s Appraisal

Ethan wakes up expecting to see the walls of a hospital room—only to find a system message blinking in front of him:[Ding! You have killed a green worm][Ding! Green worm has been added to your summoning list]

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

My name is Joo In-gong. The name that my parents gave me meant ‘protagonist’ of the world. Really?

Suzuki, an adult programmer, suddenly notices that he’s been thrown into a different world while wearing a casual clothes at level 1. He gained high levels and treasures after using the 3 times use-disposable-magic, Meteor Shower, once. After that he intends to do different world “sightseeing tours”? He meets 3 beast girls, beautiful purple and black haired sisters, and an eccentric blonde haired elf girl along with various people during his trip. Although there are occasional fighting with demons and demon lords, this is a heartwarming fantasy story at heart.