I'm the Only One with Unfavorable Skills, Isekai Summoning Rebellion seems to follow the generic Isekai Class Summoning formula that shows like Arifureta, Failure Frame, and Nito's Lazy Foreign World Syndrome possesses. It follows Yuto Nakatani and his tale after getting summoned to another world. MC gets summoned to another world. He has a skill that seems weak to everyone else despite no one testing it first. The popular kid in the class gets the "Hero" class and has a warped sense of justice. His friend and love interest is a Healer as well as finding a woman loli trapped inside the dungeon he's abandoned in.He's left for dead by everyone after helping his classmates.
The nation that summoned the group has a dark secret.

Around Chapter 7, the manga picks up when Yuto Nakatani encounters his classmates after he leaves the party. While they're killing innocent Demon Children. He then handily beats the Hero and steals several vital skills from his former classmates.

Thus begins the tale of how Nakatani became the Demon Hero.