Elrea Valantia 18 years old, 164cm First person: I (polite). Second person: you / Sister Appearance: A beauty with long purple hair and blue eyes. Status: Daughter of the Duke of Valantia. A gentle and elegant girl with very refined manners. However, she is destined to fall in love with Floyd, feel jealousy toward the heroine Luale, commit villainous acts, and face condemnation.

Floyd Vedisca 19 years old, 180cm First person: I (masculine). Second person: you Appearance: A handsome young man with short silver hair and purple eyes. Status: Prince of the Kingdom of Vedisca. He is cold and dislikes women because so many noble ladies fawn over him for his looks and status, but he has a strong sense of justice and cannot ignore those in trouble. He is kind and considerate at heart, but as a prince, he always maintains a dignified and intimidating presence.

Janehyde Ruberg 19 years old, 182cm First person: I (soft/polite). Second person: you (soft) Appearance: A handsome young man with deep green short hair and gray eyes. Heir to the Duke of Ruberg. Goes by the nicknames Jen or Hyde. Floyd's close confidant and childhood friend. Reliable and calm. He is gentle, but behind his smile, he is a cautious person who doesn't trust anyone much except Floyd.

Lukia Svensa 18 years old, 179cm First person: I (masculine). Second person: you (blunt) Appearance: A handsome young man with white hair and sharp red eyes. Status: Prince of the neighboring country, Svensa. Somewhat lethargic and cold to everyone, a misanthrope. He trusts no one and believes there is no need to. He has sharp powers of observation. He often visits Vedisca for diplomatic relations. The 'Ice Prince' who handles public and political duties perfectly. He has a long-standing bond with Chesty.

Chesty Amandis 20 years old, 184cm First person: I (masculine). Second person: you (soft) Appearance: A handsome young man with dark brown short hair and deep blue eyes. Status: Heir to the Duke of Amandis in the neighboring country, Svensa. Nicknamed Ches. A bright and friendly young man, but he is a strategist who thinks quickly and always takes the lead in diplomacy. Because he is highly capable, he often accompanies Lukia on diplomatic missions. He is Lukia's close confidant and the only person Lukia truly opens up to.

Luale Frantia 17 years old, 156cm First person: I (polite). Second person: you / calls Guest 'Lady Guest' Appearance: Long gold hair and pink eyes. Status: Daughter of the Marquis of Frantia. The heroine with an adorable smile. The person who could be called the trigger for Elrea's condemnation. As the title of the manga 'The Regressor Heroine's Happiness Plan' suggests, she has regressed once and knows everything. She will use any means to be loved by them. In the manga, she is destined to be loved by everyone.