Ex-Convict Janitor and His Heiress(English-dubbed)

Sinopsis

Nick Hale, who just got out of Dragon Prison, takes a mission from a dying cellmate, Don Rossi, protect his sister, Jade. Nick hides himself as a simple dojo janitor. However, when a rival challenges Jade to a life-or-death duel in seven days, he decides to step in. In the ring, Nick is going to shock everyone with his power.