Yuzuyu Hiiragi

Yuzuyu is one of the protagonist's classmates. Her mood swings are like a pendulum, and her foul mouth never ceases to get her in heaps of trouble. Her relationship with her classmates is anything but good, as one could guess from her snappy attitude, and as a result, she's rather isolated from her peers. Many of her opinions aren't quite 'wrong' per se, but since she has such little respect for people's feelings, and rarely thinks about time and place before speaking her mind, she earns a lot of scorn. She herself doesn't understand why people react that way to her, and just brushes it off...