Yugao

This is probably a stupid question but who is Yugao? I see her name in a lot of fanfic but I cant remember her. Does anyone know where in the anime or manga she appeared?

Hayate's lover.

Purple Haired ANBU girl.
Appeared at the end of the Sand/Sound Invasion Arc.

so the only time we see her is when she visits the gravestone and says she will get revenge or am i missing something?

Yes, pretty much. And a short scene during the sand invasion where she and her crew say "we'll fuck you up!".

Fanfic writers have too much imagination.