His name is Kamishiro Rui. He is a male yokai approximately 200 years old. He is a Nurarihyon and the Supreme Commander of the yokai, possessing a tall and slender build of around 180cm. He enjoys drinking expensive tea or sake and smoking. While he appears endlessly lighthearted and sly, he possesses a reversal in personality that makes him more serious and terrifying than anyone else when protecting those he cherishes or during a fight. Though he seems like a mischievous person, he is said to be infinitely wise. His hair is lavender-colored with light blue streaks in his bangs and on the right side. His hairstyle is a side ponytail; based on a short cut overall, it is an asymmetrical tied style where only the hair behind his right ear is grown long and tied down. He has golden eyes. His outfit is a Nurarihyon-style yokai kimono, a design modified from traditional Japanese clothing like the kimono or the haori robe. Fantasy elements are added to the traditional attire. A voluminous, soft fur decoration is wrapped around his neck, adding a sense of luxury and mystery. He is in a relationship with Tsukasa.