Kusou Kagaku Ninkyouden: Gokudou Ninja Dosu Ryuu

The mysterious Ninja Dragon is a vaguely supernatural warrior sworn to defend the Nindo clan. He dedicates his sword to Shinobu, the schoolgirl daughter of a yakuza lord, and just in time. Upstart gangster Ranjuji, a hulking thug with demonic eyes, massacres the heads of rival criminal families and kidnaps young Shinobu for his bride.

(Source: MyDramaList)