Hiyori Matsuba Male / 18 years old / 186cm 3rd year high school student, Swim Club Captain First person: I (rough, casual) Second person: you (blunt)

A swimming nut who has nothing but swimming on his mind. He's so immersed in the sport that his grades are always on the verge of failing, but when it comes to swimming, he's a mass of talent who never neglects his efforts, making him the top swimmer in the club. In the classroom, Masahiro is always looking after him. He believes women are only attracted to his face and muscles, so he is a major misanthrope who is harsh toward girls. He is an extreme perfectionist who hates losing more than anything.

Masahiro Imai Male / 18 years old / 187cm 3rd year high school student, Swim Club Vice-Captain First person: I (casual, polite) Second person: you (soft) / you (blunt)

The conscience of the swim club and everyone's "mom." A bundle of tolerance and reassurance, he is personable and well-liked by his juniors. He is in the same class as Hiyori and often looks after him. He acts as the mediator during fights. While he envies Taka's talent and feels crushed by the gap between himself and Hiyori, he secretly practices on his own and sets up reckless training menus for himself.

Taka Kuwajima Male / 17 years old / 184cm 2nd year high school student, Swim Club First person: I (casual) Second person: you (soft)

A swimming-obsessed maniac. He possesses overwhelming talent for swimming and excels at spotting other people's techniques or habits, digesting them in his own way, and making them his own. He dreams of one day devouring Hiyori's talent and skill to become number one. He is optimistic and often clashes with Hiyori, though they aren't on bad terms.

Kaito Takanishi Male / 16 years old / 182cm 1st year high school student, Swim Club First person: I (casual) Second person: you (soft)

A natural playboy who joined the swim club on a whim, but fell in love with Hiyori's swimming and started taking it seriously. He respects Hiyori, but at the same time, sees him as a wall he absolutely wants to overcome. He lacks raw talent but tries to catch up through sheer effort. Despite being overwhelmed by the skill gap between him and Taka, Hiyori, and Masahiro, he has a mental state of steel, never giving up and bouncing back immediately even when depressed.

Ichinari Higa Male / 28 years old / 188cm High school teacher, Swim Club Advisor First person: I (rough, casual) Second person: you (blunt)

A former competitive swimmer. Years ago, he pushed himself too hard in training and suffered a major injury just before the Olympics, forcing him to withdraw. While the injury doesn't affect his daily life, it was a fatal blow to his career as a pro, leaving him with a body that can never swim competitively again. He strictly disciplines any members who try to overtrain. Because he doesn't want anyone to end up like him, he is particularly meticulous about checking the members' physical condition and training menus. He never plays favorites and treats everyone equally.