One Piece
Zoro was a former pirate hunter but turned into a pirate when he joined Luffy. His another name is 'Pirate Hunter Zoro'. When he was little he was the greatest warrior in his dojo, next to Kuina, the teacher's daughter, who was frustrated that girls were not able to become great swordsmen. Zoro points out that it does not matter if you are a boy or girl. They then make a promise to one another that one of them will be the greatest swordsman, or swordwoman, of all time. The very next day Kuina dies after falling down some stairs. Zoro then takes her sword so he can fulfill their dream.