Little tyrant of Koutou. Older brother of Sonken and Shoukou. In contrast to his quiet little brother, he is a more repulsive battle type. He sent his uninterested brother Sonken to the battlefield to change his view on justice. Childhood friends with Shuuyu.

In the Clash of the Heroes Chapter together with Shuuyuu and Taishiji they start the attack at Gappi. During that battle he saved Ryuubi from the rampaging Kakuka but in turn got injured, he then leads the first move to seal the movement of Kakuka allowing the others to land the attack. After Kakuka's defeat, in the falling rubble, the heavily injured Sonsaku tell Sonken to "become the Moon that heals the people". After death he was granted life by darkness but in exchange he is possessed by Shuu.

In the Battle of the War God Chapter, he appeared in a Shuu possessed form and overwhelmed Ryuubi, Kan-u and Kan-pei, and later against Sonken who awoke as the Goutaitei. On defeat, he returned to his self, pleased with the growth of his brother he sends him off and broke down to dust.