Kira is the main antagonist of JoJo's Bizarre Adventure - Part IV: Diamond is Unbreakable. Kira is a paraphilic serial killer who has been lurking unnoticed in Morioh for years. Having lived undisturbed all his life, Kira's routine is shaken when the ghost of his first victim Reimi Sugimoto begs the Joestar Group to look for him and he attracts unwanted attention by murdering Shigekiyo Yangu. Kira is a Stand User and wields Killer Queen to create deadly bombs.

When Kosaku Kawajiri is killed, Kira assumes his facial features, including his spiky black hair, thin, large dark irises, and higher cheekbones - becoming Kosaku-Kira. He retains his suit, changing only his tie to his normal Skull tie.