He has blue hair and is incredibly strong, with a huge appetite. He becomes romantic rivals with Shiine after the young magician takes an interest in Chacha.
Riiya has a grandfather who is very big, and many werewolf brothers. In the 23rd chapter in the original manga, it was revealed that Riiya's parents died when he was very young, but he doesn't know that since Seravy had lied to him that they live on the second floor of his house.
Throughout the anime, Riiya's werewolf form slowly changes from a realistic look to a more cartoonish look. The most noticeable difference are the eyes as they get rounder and bigger and less realistic.