Rika Saionji

Upon chapter 65, not much is known about Rika Saionji. Via Leona Miyamura, it is learned that she has the ability to make a person lose memories about the witches. However as of chapter 66, it is revealed that her power is actually a power to wipe out everybody's memory about that person (without having to kiss that person directly).

Rika Saionji has the ability to make a person's acquaintances lose all memories about the witches. This ability is activated without having Saionji kiss that person. In exchange, however, the effect takes 24 hours to manifest.