Ryūrimaru

was Hisen's summoning creature that appeared in the light novel adaptation of Mission: Protect the Waterfall Village!. Ryūrimaru was summoned by Shibuki in his battle against Suien.

Appearance
Ryūrimaru is a crimson white catfish that was six times the size of a human man.

Personality
Ryūrimaru was obedient and loyal towards his summoner, Hisen.

Abilities
Ryūrimaru had the ability to use the Transformation Technique. With Hisen saying, "Dragon God Transform", Ryūrimaru transforms into a giant golden dragon.