Ryuuhei Midou

Ryuuhei is Kouhei's grandfather and a powerful spiritualist. Kouhei lives in his household, which is located in an antique shop. He agreed to take Hazuki in out of kindness, though he appears to have other motives for it as well including ascertaining the whereabouts of his daughter Shizuru (Kouhei's mother).

(Source: Wikipedia)