Kikyou

Kikyou is a demon who was conjured by Makoto's grandfather, the previous head of the family. Normally, a demon always accompanies her master into the afterlife, but Kikyou somehow remained behind in order to support Makoto. Demons are invisible to the naked eye and possess powers beyond human comprehension, but neither of those applies to her.
Generally, she appears calm, kind and reserved, looking exactly like an ordinary person, but when she gets mad...