森谷 毬枝

A kind-natured and timid girl that is a victim of bullying. Eventually, her teacher, Kanamori Yoshihito, starts to molest her. She is a member of the animal raising committee.

Kanamori becomes paranoid about Marie eventually revealing their "relationship", and strangles her to death when she tried to confront him (Marie planned on reporting him to the authorities, using the video recordings Kanamori made as evidence against him). He was also competing alongside Marie in the hopes of becoming Mesomeso-san, but was killed because he broke the rules of the "game" (speaking to Meso-Meso).

Marie is now the School Youkai of the 8th rank. School Monster, Mesomeso-san. A youkai rumoured to live in the former school building's bathroom. Even if one hears it talking through the door, the must not reply. Unimpeded in her youkai form, she became stronger than she was in life.

Instead of going on the occasional hunt, she sometimes sneaks into the cafeteria. She also possesses a mysterious ability to find tea cakes from seemingly thin air.