Yuri Koigakubo

The homeroom teacher of Class 2-C. She is 29 years old at the beginning and turns 30 during the story. She is somewhat laid-back and unable to read the room, and on top of that, she is timid. Being single, she tends to dress up noticeably whenever there is a chance she might get a boyfriend or get married. However, she handles her duties and responsibilities as a teacher properly and has gained a certain level of trust from her students. As the series progresses, her single status and age become increasingly emphasized, leading to teasing from students with remarks like "Single!" or "Thirty!" and her name in the text being noted as Single (30). She is the protagonist of the spin-off "Sensei's Favorite."