Ryusei no Sōryūha

is the upgraded version of the Sōryūha inherited from Sesshōmaru and used by his elder twin daughter in just one episode of Hanyō no Yashahime 's second season.

Trivia

 * This variant/evolution of Sesshōmaru's signature attack, Sōryūha, has only been used once in Episode 44 due to harnessing the infinite cosmic demonic energy of the Grim Comet itself, which had strengthened its attack power and effectiveness tremendously. Once the Grim Butterfly had vanished from existence, and the almighty Zanseiken returned to its rightful owner, this evolved version of said attack was never utilized again, restoring Towa's inherited Azure Dragon Wave attack and her upgraded/evolved Twin Azure Dragon Wave to their standard power levels.