Many years after the Kakashi Gaiden she became a member of the Anbu Black Ops and rose quickly up the ranks. She is first Introduced in the anime as one of the Anbu Black Ops discovering Hayates dead body. In a later episode during the destruction of the leaf village saga she is seen near the large K.I.A stone Kakashi is usually standing around paying respect to Obito, Rin says "Hayate I will avenge your death" in the English Dubbed version and then leads her squad into the Village to fight off the invaders. It was obvious that her mission was a success seeing as during Sarutobis funeral her and Kakashi are having a conversation near the stone."
Lol and here i was thinking you put some thought into that. Plus that is wrong, i don't think that particular anbu member was seen without a mask off, besides she could be someone kakashi met during his time a anbu member.This is wrong Its juat what i saw on yahoo
Edit: And it just so happens to be the person posting before me confirms this.