Reikan Ryuudou is Issei's older brother who helps run Ryuudou Temple. He is friends with Taiga Fujimura and Otoko Hotaruzuka.

Reikan is a very responsible person. Issei tries to act in the same manner and follows him as a role model. Reikan is very fond of martial arts, training frequently with Souichirou, and takes his role and his duties very seriously. He dislikes having a woman (Caster) living in the temple, but he does not dislike her personally.

(Source: TYPE-MOON Wiki)