Oosumi Orihiko, an Ashikabi, first appeared during a flashback from Homura when he recollects his activities as Sekirei Guardian and was seen a second time watching the first match of the third stage of the Sekirei Plan with his Sekirei Kaho. His name was revealed in the beginning of the 4th match of the 3rd round when other Ashikabi described them as quite strong. He later defends together with his Sekirei Minato and Kusano. He is supportive of his Sekirei's wish to thank Homura for her rescue and because of that makes sure that Minato doesn't get defeated and consequently Homura terminated.
Oosumi is an avarage-sized young man with short messy black hair. He wears black pants, a grey short-sleeved shirt with a white wife beater underneath.
Oosumi appears calm and collected even in battle situations in which Minato is visibly distressed. He is also quite informed about the Sekirei Plan and his participants showing he isn't in favor to rely on luck.
- No 87 Kaho (terminated by Karasuba)
Nothing is known about his past.