Nanafushi

Nanafushi was a ninja who hailed from the Land of the Valley. He was set to steal Konoha's secrets. He used the transformation jutsu to be Might Guy. As he entered the village, Naruto thought he was the real Might Guy and took him to Rock Lee's dojo. After a few fights and after Guy came back and fought Lee who was at the time Nanafushi using his trasformation jutsu again as Lee. Then later after finding out who he really is, They took him in to the Fifth Hokage and got him arrested.