Jaryuki is the legendary monster that was defeated by The Warriors of Sirius hundred years ago. He is described to have a "body of a snake, five heads and ten legs". Hokkaido wolves gained the special abilities by eating the dragon's flesh.

Jaryuki only appears in a story told by Reima. Meteor Gin suggest that the legendary giant snake monster was made up by wolves, who exaggerated the story over the generations. It also suggest that the idea of Jaryuki might come from Yamata no Orochi - an eight-headed snake from Japanese myths.