Mari Shiina

Mari Shiina is is one the major supporting protagonists in the anime/manga series Love Tyrant. She had every intention of waiting for Kusunoki-sensei to confess to her, and she wants to wait for her to graduate and get a good-paying job, since teachers don't have a good salary. She is fully aware of Kusunoki-sensei's feelings for her and she returns them.

Sniff Sniff x The Only One Who May Hurt Seiji-kun... Is Me
One of their teachers Mr Kusunoke, is in love with one of their classmates, Mari. The girls decide to find out if the two would make a good couple, despite being a teacher and student. Mari claims to think of Mr Kusunoke as a little brother. Guri plans to fake taking Mari hostage so Mr Kusunoke can rescue her, however real criminals take both Mari and Guri hostage and Seiji is shot protecting Yuzu, causing her to develop feelings for him. Mr Kusunoke tries to protect Mari but is too weak to be of help.

Mr Kusunoke tells Mari that to confess his love would be inappropriate and will wait until she is no longer his student. Mari reveals she feels the same way but had likewise been waiting to tell him. She also privately tells Seiji that she loved Mr Kusunoke first and secretly manipulated him into falling in love with her.

Personality
Mari is kind, nice, loving person. However, she also sometimes to tease some of the main characters like Seiji, and can be secretly manipulative like she did to Kusunoki.