Fumio Tatesako

Fumio Tatesako is Recca Hanabishi's Japanese History teacher. He knows a lot about ninjas and is espicially interested in the Hokage ninja. He lives in a temple. Kurei ordered Kaoru and Mokuren to kidnap him since he was knew too much about the Hokage. He knows about Recca's predicament and allowed Team Hokage to skip school to enter the Dark Martial Combat. He also enjoys beating Recca at Playstation games. He is married. 

Source: http://flameofrecca.wikia.com/wiki/Fumio_Tatesako?file=Fumio2.jpg