Studied thogether with Ryuubi under Soshoku. Following in his father's steps, he aims to become a general of the Yuushuu army. Before Roshoku was executed Kousonsan was trusted with Roshoku's records on the art of war. After that he was victorious in a battle and was promoted to a general with Chou-un as his subordinate.
Died in the battle with the Kishuu Troops. Kousonsan and his troops announce their surrender but was tricked to drop their weapons. His men tried to protect him from the arrow shower but he went forth and too perished in the arrow shower.