The assigned SS Agent to Ririchiyo and her servant, Sōshi is the reincarnation of the evil Nine-Tailed Fox. Ririchiyo helped him when she was little. Later on in the series, it is apparent that Ririchiyo had changed him in a way. Very calm, polite, and gentle to people, he has a soft spot for his mistress, blindly obeying her and protecting her with his life if the situation calls for it. What he wishes for is a family, which he never had.
A notable feature is his Heterochromia: his right eye is blue, while the other is a dark gold.