Maria Otonashi

An antisocial beauty with a resolute personality. She transfers into Kazuki's class on March 2nd—right before the end of the school year. Immediately upon her arrival, she announces her intent to “break” Kazuki.

Her life first intertwines with Kazuki when she sneaks into Mogi's box that created the recurring classroom. Being a box herself, she is able to keep her memories each recurrence. She spends years searching for the one who has the box and created the recurring classroom. During this time she also spent lots of time obtaining new skills, such as martial arts and how to ride a motorcycle.

In the final volume Maria and Kazuki get married.