Usuba Sumi

Miyo's biological mother, now deceased. She was the first wife of Shinichi Saimori. Although she is often referred to by her maiden name in the novel, when touching upon the period from giving birth to Miyo until her early death, she is sometimes referred to as Sumi Saimori. During her student days, she used the alias Sumi Tsuruki.

Despite her weak ability, she could use the psychic power of telepathy, and was expected to give birth to a child with the power of foresight. To ensure that Miyo's power of foresight remained hidden, she sealed Miyo's abilities in such a way that it continued even after her death.