I Leveled up from Being a Parasite, But I May Have Grown Too Much - Chapter 122: The Lunch Avenger

Noah Brown had a gift for fighting. Unfortunately punching things didn't pay the bills, at least until he died and an Eldritch god found his soul. The encounter led him to a new world, summoned by bloody cultists, with nothing but the shirt on his back, and a strange item in his system menu.

[???] : A source of infinite potential.

Perhaps he'd finally get to put his gifts to good use.

“Darling, I want…”

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