To test Kenshiro's worthiness as the "messiah of the end of the century", Ryuga allies himself with Raoh and becomes one of his lieutenants. He wishes to stabilize the turbulent new age they live in, but Ryuga is also keen to see if Kenshiro can reach his full potential. Committing several horrendous acts, including an assault on the heavily ailed Toki, his actions ignites the younger brother's anger in a final confrontation. To Kenshiro's surprise, Ryuga accepts his punishment with little resistance as he had intentionally hurt himself before their fight. He reveals his true duty is to guide and test who was actually worthy to lead the new age: Kenshiro or Raoh. Accessing that the kinder younger brother is more worthy, he gladly expresses his belief in Yuria's assessment before dying from his wounds. Toki's spirit lifts his body after his death and they both become stars in the heavens.
Role in Super Smash Sisters
Ryuga appears non-playable in Super Smash Sisters. He wears his Hokuto Musou getup. In fighting, he uses his Taizan Tenro Ken style which can leave an opponent feeling cold before he dies.