Shikō Sōjin is a third-year student at Kyosho Academy, aged 17 and born on May 16. She stands 161 cm tall with body measurements of 78-56-82 cm, black hair, green eyes, and blood type O. Officially ranked Toushi B, she personally claims A-rank status. Her role involves leading and managing the academy's lower-ranking fighters.

Sōjin displays a tomboyish personality and a quick temper, especially when her femininity is insulted. This anger flares when a combat distraction tactic—flashing her shorts—fails, and her own subordinates mockingly attribute the failure to her "boyish" appearance.

During an assault on Seito, Sōjin wielded one of the Hyakuhekitō weapons but failed to breach defenses led by Kanshou. Her distraction attempt backfired, resulting in her being knocked unconscious.

In the *Xtreme Xecutor* storyline, she witnessed Bachō Mouki's confrontation with Sousou Moutoku at Kyosho Academy. Later, she was chosen alongside Chuukou Kyocho as Kyosho's representatives for a tournament on Nanban Island. This event proved to be a trap, leading to her capture by Nanban fighters. While imprisoned, she identified Ten'i among the attackers, providing a vital clue to the identity of the enigmatic Kentei.