"we don't need a tank"
famous last words of MMO guild before they face an actual boss. I get this dude just wants to kick out MC and have the friend to himself (lol), but at least pretend to have a replacement instead of making some D-level guild mistake like this.
it's very similar to
https://mangadex.org/title/1487ed38...-koibito-ni-tsuihou-sareta-senshi-no-mujikaku
MC is in s rank party with friend/potential lover, then jealous blonde "friend" steals her away and kicks MC out of the party. MC unlocks a rare skill then frees a slave (that's really only a slave in name. She's more or less just a partner that fell in love) that he can make OP and one-ups pretty boy on a bunch of missions.
diverges a bit since this MC is just doing one huge mission instead of a normal string of adventures, but it's bizarre how they blend together.