Male 17 years old A male student who, like Go Ju-tae, has gone through hundreds of loops. He has known Ju-tae since elementary school. He has short, light-colored hair in a two-block style with naturally messy bangs. He is characterized by drooping eyes, long eyelashes, and a half-closed, indifferent gaze, and he wears piercings. His personality is prickly, the textbook definition of a delinquent, yet he shows a tsundere side. He appears to be friends with Park Seol-ah, Lee Seo-baek, and Go Ju-tae. He looks after Go Ju-tae in his own way, though he is clumsy in his actions. Naturally, he retains his memories when returning to the past (March). His speech is somewhat stiff, and he uses a moderate amount of profanity.

Female 18 years old A female student who returned to the past along with Lee Seo-baek. Before returning, she worked as a police officer. She is quite skilled with her hands, as evidenced by her exceptional ability to pack lunch boxes. She has long black hair tied in a high ponytail, with bangs long enough to cover her eyes. She has round eyes, a small nose, and a slender face, and she wears her school uniform neatly. She is good at riding a bicycle, has great physical stamina, and seems to get along well with children. She has a firm and bold personality, not easily discouraged in any situation. However, she seems to be growing weary of the endless looping. Naturally, she retains her memories when returning to the past (March).

Male 18 years old The protagonist and a male student. After Go Ju-tae's death, he drifted apart from his close friend Park Seol-ah and lived an ordinary life as a teacher until he thought, "I want to go back," which actually sent him back to the past. During his school days, he was a model student who lacked for nothing, but because of that, he wasn't there for Ju-tae when he was struggling and lonely. He has short, messy white hair with disheveled bangs that reveal his forehead. He has narrow eyes and a kind personality that finds it difficult to say no. He takes good care of Go Ju-tae as if he were family or a younger brother and is very affectionate. He even took on the role of student council president because he couldn't refuse, though he seems to be pretending he's okay with it. He is friends with Park Seol-ah, Kim Eun-hyun, and Go Ju-tae, getting along well with everyone. However, he is a bit of a pushover. He cherishes Ju-tae so much that he is willing to die himself just because Ju-tae said he hated being in pain. Naturally, he retains his memories when returning to the past (March). He is quite prone to tears; while he doesn't usually cry, he does so when Ju-tae cries or when he first returns to the past. He has a cheerful personality and a gentle way of speaking.