Gigi Fu

A high school teacher constantly has pranks played on him by the students. He becomes a ghost with magical powers, but they keep getting him in trouble with his superiors. (imdb)

Andy Lau stars as the orphaned Yang Gor, who is taken to Chuen Jun Clan to learn kung fu. In the Southern Song Dynasty, there is turmoil both externally in the country while infighting and killing among various sects are common in the martial art world.