Sophia Pistis

She is a mysterious existence that takes the form of Karin and only Kenta is able to see her outside of a dream.

When a person is bitten by Karin, part of her is transferred within the person.
In the person's dream, she takes form of the person who is most important to them.

She is the younger sister of the Akuma twins, and shares her name with Shizuki (the eldest twin) for reasons unknown.