Kensei Muguruma is the captain of the Ninth Division of the Gotei 13 and a Visored.

Over 100 years ago, Kensei was dispatched to Rukongai to investigate numerous mysterious disappearances there. While camping out that night, Kensei's unit was attacked by one of their own as part of Sōsuke Aizen's experiments. As a result, Kensei was transformed into a rampaging Hollow. After being saved by Kisuke Urahara and Tessai Tsukabishi, Urahara used the Hōgyoku on Kensei, turning him into a Visored. However, the Central 46 sentenced him to be killed as a Hollow. Urahara, Tessai and Yoruichi Shihōin helped him to escape to the Human World where he would later take part in the battle to stop Aizen in the fake Karakura Town. Some time after the battle, he returned to his former position as Ninth Division captain, replacing Tōsen.