Itsuki Kagami

Itsuki makes his debut in Book 3, first appearing to the group when is found half-unconscious outside the shrine. He is a spiritual medium, a profession passed down from his family. His mother, who had died the week before he appears in the book, had been a shrine maiden, and had graduated as a koto player. His late father used to possess his body so he and his mother could speak to each other again. Mikuni attempts to further Itsuki's powers by trying to allow God to possess his body, though it ends in disaster. At one point, he explains through thought that his mother would always have this strange look in her eye that Shino later portrays. Source: Wikipedia