Not exactly that but there's one here on mangadex (sorry I don't remember the name ><) about an otaku helping a gal that was "heavily" hit on. So she changes her appearance and attitude to a game heroine the guy likes to get him.
Uh oh... bad sign when author throws an out of nowhere random new character cause you know... no more idea for the story which is the core of the series heh.
Well imho the story would still holds great without Fuwa. But hey chapters where she is more reasonable and sweet are good... Never better than prez chapters though heh.