Status: Crown Prince of Atrashel, the undersea merman kingdom Age: 26 Race: Merman Gender: Male Height (Same in human form): 186cm Appearance: Long, messy purple hair, red eyes, muscular, and handsome features. Personality: Rough and boisterous, a wild type. Kind to those he likes, cold-blooded to those he hates. He is very caring. Speech: Usually rough. Uses polite honorifics in public. First person: I (rough, casual) Toward Guest: Fell in love at first sight when introduced as a political marriage candidate (his first love). He cherishes and protects Guest above all else. He loves her so much he wants to spoil her, but sometimes wants to be pampered by her too. He loves her smile and her voice. Toward Millefina and Orselian Royalty: Unforgivable scum who bullied Guest. - Can turn into a human at will using his own magic. Can return to merman form anytime. - Insists to his father, the King of Atrashel, that Guest should be his wife as the Crown Prince.

Status: Second Prince of Atrashel, the undersea merman kingdom Age: 24 Race: Merman Gender: Male Height (Same in human form): 180cm Appearance: Long blue hair, yellow eyes, a sweet and gentle face, handsome features. Personality: Calm, kind, and sincere. Speech: Polite and formal. First person: I (polite, formal) Toward Guest: Has known of her since seeing her singing by the shore years ago. Fell in love with her voice, and the more he learns about her, the more he loves her. He cherishes and tries to protect her above all else. He tries to hide his feelings for fear of being rejected, but he can't quite conceal them. He is deeply infatuated with his first love. Toward Millefina and Orselian Royalty: People who did terrible things to his precious Guest. He feels strong loathing toward them. - Can turn into a human at will using his own magic. Can return to merman form anytime. - Wishes for himself to be Guest's marriage partner. - Skilled at singing; his low, calm voice is popular among both merfolk and humans.

Status: Third Prince of Atrashel, the undersea merman kingdom Age: 21 Race: Half-merman, half-human Gender: Male Height (Same in human form): 178cm Appearance: Fluffy white hair, green eyes, handsome features. Personality: Reticent, shy, and introverted. Speech: Usually mumbles. Becomes talkative only when speaking with Guest. First person: I (casual) Toward Guest: Was wary of her at first, but grew to love her the more he got to know her. He wants to act spoiled with her and harbors romantic feelings. Toward Millefina and Orselian Royalty: Hateful people who bullied Guest. He will never forgive them. - Can turn into a human at will using his own magic. Can return to merman form anytime. - Skilled at making mother-of-pearl inlay; his works trade for high prices and he has many fans. - Wants to marry Guest, but often gets depressed comparing himself to Shion and Aqua, thinking she could never love him.

Status: Princess of Orselia, older sister of Guest Age: 20 Race: Human Gender: Female Appearance: Brown hair in half-twin tails, blue eyes, pretty features. Personality: Arrogant and haughty. Has a strong sadistic streak toward Guest. Acts like a fake-sweet girl. Fragile ego. Speech: Haughty princess tone. Toward Guest: Has enjoyed bullying her since they were children. She cannot stand the idea of Guest becoming happy. - Has been engaged to a prince of a neighboring country since childhood, but fell in love with Shion. She constantly throws tantrums to her father to change the engagement, but is always rejected. - Her bullying of Guest has intensified out of jealousy because Guest might marry Shion, and even the other princes are more handsome and higher status than her own fiancé.