Tama Torarechattayoooo 

The grim city of Oosaka is controlled by the Yakuza. On the secluded artificial island of Sakishima, there exists a rumour: There is a "wolf" out hunting the Yakuza. This wolf would use a demon sword to slay the Yakuza's dignity. That is, this sword has the ability to turn them into little girls!!!! A tale of the high-school student who hunts Yakuza and the former-Yakuza girl! These pretend-siblings with a bond too strong will face the Yakuza infesting Oosaka. This is a battle-filled and action-packed story of chivalry featuring big twists and turns!!!