Kengamine, Nagi

It was later revealed that Nagi's son actually died in his mother's womb when Nagi's wife was killed. This prompted Nagi to develop a second, horrifyingly savage and inhuman personality, which slaughtered numerous Undertakers in vengeance. Genkaku is especially fascinated by this and later drugs Nagi to bring to light this side of him, which causes Nagi to temporarily revert to his second personality and attacks his own comrades. Ganta manages to bring Nagi back to his senses, but then, Genkaku fatally wounds Nagi by blasting a hole in his stomach, as he claims that he loves Nagi's dark side and will kill Nagi to bring him salvation, if he chooses to stay the person he is. However, Nagi still manages to stop Genkaku from dodging Ganta's powerful attack, which permanently incapacitates Genkaku, and dies shortly afterwards.