Derived from the game League Of legends a Yasuo main has accomplished nothing and will never do anything in his life, they are usually stuck in this bubble where they think are awesome because they play someone who takes no skill.
yasuo main: hi i'm a yasuo main
normal person: you shall be purged with fire you waste of space
Usually some 12-13 year old who's trying to be "cool" and "edgy" but ends up making themselves look like a fucking tool in the video game Team Fortress 2.
Little shit: I'm going to be a scout main and no one will stop me!
Actually respectable and good player: stfu and go download garfield cart or something.