Ryougo Nagitsuji
He is childhood friend of Rokuro. When Rokuro first came to Hiinatsuki Dorm, he was to one who took care of Rokuro and made him cheer up. From then on they have been best friends.
Later on he moves out from Hiinatsuki Dorm to become a exorcist. So he was not there to witness Hiinatsuki Dorm Tragedy.