The main antagonist of JoJo no Kimyou na Bouken Part 4, Diamond is Unbreakable.
A serial killer who uses his Stand, Killer Queen, to kill beautiful women for their hands, which he finds extremely attractive. He typically dresses in a suit with a distinctive skull-print necktie (example: post #404241).
After his identity is revealed to the main cast, he manages to switch all his identifying features with those of Kawajiri Kousaku and steals his identity.