Myousai Kakouen is an assassin for Kyosho Academy, distinguished by long jet black hair, crystal blue eyes, an all-white tunic, red gloves, and white high-heeled boots. Her expression remains minimal and rarely shifts, a result of childhood trauma sustained during warfare in Southeast Asia. Rescued from imminent sexual assault by a soldier—who was then killed either by her or Sousou Moutoku—she was discovered wearing army fatigues. This forged her absolute, unwavering loyalty to Sousou, defining her core purpose: to protect and serve him. In *Ikkitousen: Dragon Destiny*, she pursues the Dragon Jade to save Sousou's life, targeting Shimei Ryomou. Their clashes occur at a collapsing shrine, Ryomou's hotel, and later during Kyosho's invasion of Nanyo Academy where Kakouen overpowers fighters including Gakushuu. At the Battle of Red Cliffs, she confronts Ryomou again but falls to a combined chi blast from Ryomou and Saji. Surviving this defeat in *Ikkitousen: Great Guardians*, she leads Kyosho Academy temporarily in Sousou's absence. Desperate to restore Kyosho's strength, she allies with a mysterious girl (later revealed as Genpou Saji) to find Sousou and recover the missing Kakouton. Kakouen distracts Kakouton to aid Ryofu's capture, nearly defeating him before Hakufu Sonsaku intervenes. Kakouton later defeats her, promising to return to Kyosho when ready. Under Saji's hypnotic influence, she viciously attacks Kakouton and Koukin, breaking free only when Sousou reappears and dispels the hypnosis. She subsequently returns to Kyosho with Sousou and Kakouton. She reappears in Japan with Sousou's group in *Ikkitousen: Xtreme Xecutor* after they recover Teni, though her specific activities or motivations in this arc remain unspecified. Her combat prowess is significant. She wields the "Jade Shot," a projectile on a long metal wire used for restraint and pressure point attacks. Officially an A-Rank Toushi, she exhibits high durability, pain tolerance, and pressure point expertise. Her pragmatic, mission-focused fighting style occasionally yields respect for skilled opponents, like Chou'un, recognizing their shared dedication to protecting someone important. Her character development remains centered entirely on loyalty to Sousou, persisting through temporary leadership and external manipulations like hypnosis. She consistently returns to Kyosho and Sousou's cause after major conflicts.