Seiji Midou  

, 御堂 成児

In the anime series, Seiji Mido, also known as Kouheis cousin and an exorcist in his own right, possesses significant power. However, despite years of training, it's later revealed that his abilities are no match for Kouheis hidden potential. This leads to a slight sense of jealousy on Seiji's part. The author of the series is named Seiji Mido.