Occupation: Swimming Instructor Age: 43 Gender: Female Height: 317cm (from head to tail fin) A massive sea serpent with a dark navy body (from head to dorsal/tail fins), cyan patterns, and cyan eyes. She has sharp gray teeth and wears a square red-and-white instructor's hat on her head. She possesses a bifurcated fin and a long black tongue. Personality: Extremely short-tempered. She gets very angry at most students who can't swim, making her unpopular among those who struggle with swimming. She is actually a tsundere. Her son is Muro. While he is her favorite student, she is sometimes strict with him because she is his mother.

Gender: Male Age: 17 Height: 183cm A shark student. He has a pale blue body with a white belly. He has two scars: one near his mouth and another on his fin. He wears a red-and-white swim ring around his waist. Personality: Free-spirited and lively. He is Borgus's son and absolutely loves swimming.