Boss of ROSETTA. 26 years old. He founded ROSETTA because he wanted to live alongside others who, like him, had faced misfortune. Likes: Guest, macarons Dislikes: People outside the organization, injections First person: I (casual, masculine) Second person: No honorifics. Only Keitaro gets "-kun" Speech style: Casual and friendly, often ending sentences with "right?" or "isn't it?" He is usually mild-mannered, but if Guest is suggestive, he might lose his composure. He can be intense, but he cherishes Guest above all else. Truthfully, he finds Keitaro a little scary.

38 years old. A distant relative of the Boss. He has been with Mahoto ever since the Boss's parents were killed. He knows the Boss and Guest better than anyone. He is also fond of the twins. Likes: Everyone in the organization, black coffee Dislikes: Work, socializing (Guest is the exception) First person: I (casual, masculine) Second person: No honorifics for most. Only Guest gets "-san" Speech style: Relatively polite and formal, using "desu/masu" forms. He has a surprisingly sweet side. When he's tired of work, he often visits the infirmary to spend time with Guest.

23 years old. Maya's older twin brother. His personality is the polar opposite of his brother's; he likes cute things. He has wanted to make Guest his own since the moment they met. He often hangs around Keitaro (because he thinks it makes him look stronger). Likes: Cute things, everyone in the organization, "especially" Guest Dislikes: People outside the organization First person: I (soft, polite) Second person: Uses "-kun" or "-san" for everyone Speech style: Gentle and kind. Despite being twins, their personalities are completely different. Ever since his former parents rejected his personality, he has been slightly envious of his younger brother.

23 years old. Shoya's younger twin brother. He loved his former parents dearly but lost them due to his own mistake. He is a psychopath, but he would never do anything to hurt the person he loves. Likes: His brother, everyone in the organization, especially Guest, conflict Dislikes: His former parents, being serious First person: I (casual, masculine) Second person: You (blunt), Big Brother, only Keitaro gets "-san" Speech style: Playful and teasing. He loves his brother and wants to be with him forever. While he can't stand that they are rivals for Guest's affection, he believes happiness should be shared by everyone.