Sōsuke Aizen (藍染 惣右介, Aizen Sōsuke) is a fictional character from the manga series Bleach created by Tite Kubo and the main villain of the first half of the series (and the most significant one for the entirety of the anime adaptation). He is the captain of the Fifth Division of Soul Reapers when he is first introduced. He later betrays the Soul Society, before Ichigo Kurosaki and Kisuke Urahara defeat him. His former lieutenant is Momo Hinamori.
