What is "sekirei"

is a Japanese manga series by Sakurako Gokurakuin. The manga was serialized in Square Enix's seinen magazine Young Gangan between December 2004 and August 2015. An anime adaptation produced by Seven Arcs and directed by Keizō Kusakawa aired in Japan between July and September 2008, and a second season aired between July and September 2010. Both seasons are licensed in North America by Funimation. The central character of the series is Minato Sahashi, a ronin who failed college examinations twice. His life changes, however, when he meets a girl named Musubi.