Zerozaki Kishishiki no Ningen Knock

Third in the ranking of the "Assassin Name" families of the underground assassin community, the "Zerozaki Ichizoku" is infamous for their indomitable family unity. Each of its members exhibit combat prowess when it comes to saving one of their kin. Zerozaki Kishishiki is one member of the Zerozaki family, and he utilizes a bat covered in nails to brutally murder his targets. He calls his weapon the "Praise of Folly (Seamless Bias)." His next target was supposed to be an ordinary target, just another day for him. He faces a problem when he discovers that he has become prey to a formidable enemy.

(Source: MangaHelpers)