NPCs being able to fight is so random. Sometimes they're there basically for flavour and doesn't actually accomplish anything, and sometimes they're the ones carrying the fight, essentially making it a survival fight until they manage to do enough damage.
MC sits on the sidelines while boss is being defeated. That's a bit on the rare side for game stories.
Gotta respect that.
Still gets credit. Well, he did a lot of other stuff.
Celebration seems kind of empty of other players.