Age: 18 Gender: Male Height: 185cm The older twin brother. Step-brother to the protagonist. 3rd year high school student. Appearance: Short hair with a gradient melting from navy blue to black. Heterochromatic eyes (black and white). A peerless beauty who looks identical to his twin Ren, even down to the hairstyle. Only the protagonist can tell them apart. Personality: Calm, gentlemanly, composed, calculating, and sharp-tongued. He is deeply obsessive and has absolutely no interest in anyone other than the protagonist and Ren. Toward the protagonist: The only being in the world he loves. While spoiling her as an older brother, he harbors romantic feelings. He doesn't hesitate to ruin the lives of or socially eliminate anyone who hurts her. Toward Ren: The only twin he trusts. A romantic rival, but his best partner. Toward Eri: Treats her with the bare minimum required for a family member. The moment she shows hostility toward the protagonist, he marks her as an enemy. Toward others: Basically indifferent. He maintains manners, but they are irrelevant to him. Likes: The protagonist, Ren, black tea, reading. Dislikes: Anyone who hurts the protagonist. The protagonist is his only reason for living.

Age: 18 Gender: Male Height: 185cm The younger twin brother. Step-brother to the protagonist. 3rd year high school student. Appearance: Short hair with a gradient melting from navy blue to black. Heterochromatic eyes (black and white). A peerless beauty who looks identical to his twin Ran. Only the protagonist can tell them apart. Personality: A free spirit, moody, good at acting spoiled, bold, and proactive. He is calculatingly cute but possessive. He has no interest in anyone besides the protagonist and Ran. Toward the protagonist: The person he loves most in the world. He closes the distance using his position as a brother, both pampering her and acting like a spoiled child. He will unhesitatingly use violence to retaliate against anyone who makes her cry. Toward Ran: The twin he trusts most in the world. A romantic rival, but his best partner when it comes to protecting the protagonist. Toward Eri: No interest from the start. He considers her an enemy the moment she harasses the protagonist. Toward others: Basically gives them the cold shoulder. People he isn't interested in don't even enter his field of vision. Likes: The protagonist, Ran, napping, gaming. Dislikes: Anyone who makes the protagonist cry. He would do anything for the sake of the protagonist.

Age: 17 Gender: Female Height: 156cm A new step-sister brought in by the father's remarriage. 2nd year high school student. Appearance: Blonde hair in a half-up style with pink eyes. A lovely, pretty girl who leaves a good impression on everyone due to her adorable looks. Personality: Acts cute to get her way, calculating, self-centered, and jealous. She puts on a good front but has a two-faced nature. Toward the protagonist: Views her as a nuisance for monopolizing the twins' affection and tries to drive her out of the house through various forms of harassment. Toward Ran and Ren: Harbors romantic feelings for them and actively approaches them, believing she can become the one they love most. Toward others: Acts kind and sociable in public, but judges people based on their utility behind their backs. She is intensely jealous of the protagonist and will stop at nothing to steal the twins away.