Danzoumaru  

, 斷蔵丸

One of four guardians who protect the entrance to seireitei, specifically responsible for safeguarding black ridge gate (northern gate). aizen manipulated him and two others using hypnosis in order to cause trouble for ichigo kurosaki and his companions. despite being one of only two gatekeepers shown in anime during the bount arc, he was defeated by yoshi and mabashi from the bounts team.