The Sekirei manga features an extensive cast of characters created by Sakurako Gokurakuin. The story centers on Minato Sahashi, a high school graduate trying to get into college, who becomes involved with Musubi, one of 108 Sekirei: super-powered beings that are predominantly female with unique powers who must fight in a battle royal called the Sekirei Plan. He becomes her Ashikabi, a human with special genes that allow him to activate a Sekirei's powers through "winging", which can be a mouth-to-mouth kiss. Minato soon leads a team of Sekirei residing mostly at Maison Izumo, a boarding house in North City, and must face opponents in the form of other Sekirei, many of whom have teamed with other Ashikabi and are spread throughout the districts of North City as well as other cities. Overseeing the Plan is a group called Mid Bio Informatics (MBI). New Sekirei and characters are also introduced in the media adaptations including the anime series and the video game series. Sekirei characters have had mixed reception among the Japanese and international anime communities.
The protagonists are residents of Maison Izumo (出雲荘 Izumo-sō?), a boarding house in North City. The house was built by Takehito Asama and Kaoru Seo. Miya is the current owner and landlady.
Minato Sahashi (佐橋 皆人 Sahashi Minato?) is a high school graduate who had failed the college entrance exams. After meeting Minato at the start of the series, he becomes an Ashikabi. Over the course of the story, he wings several Sekirei and they share a residence in Izumo where he has his own room. He has a passive and somewhat cowardly personality, but over time, due to the kindness and love of his Sekirei and his desire to protect them, he becomes more confident and "manly". He often places himself in the path of danger to protect his Sekirei from harm and avoids situations that pose a high risk of danger to prevent his Sekirei from engaging in needless fighting. Although many of his Ashikabi peers consider these actions cowardly, Minato finds that his Sekirei have become endeared to him. Minato's known family consists of: his mother Takami; his grandmother, whom Minato stated could live another 100 years; and his younger sister Yukari. It is later revealed that Hiroto Minaka, MBI's director and CEO, is Minato's father.