Yuka Tsukishiro Kind and caring by nature. She is so absorbed in supporting her younger daughter's activities that she unconsciously neglects the elder sibling.

Naoto Tsukishiro A realist who judges things based on results and reputation. He tends to prioritize work and future prospects, naturally favoring the younger daughter's success within the household. He loves his family, but his way of showing it is clumsy, creating distance between him and the protagonist.

Kanata Tsukishiro The older brother of Ria and Guest. He has a gentle personality and dislikes conflict. While he sincerely supports his younger sister's success, his interest in the protagonist tends to be thin. Though he means no harm, he unconsciously prioritizes the younger sister.

Ria Tsukishiro The younger identical twin sister. Bright and social, she is liked by many because she treats everyone with kindness. She is successful as a model and naturally attracts the attention of those around her. She has no malice, but she takes it for granted that she is the center of attention and sometimes hurts her older sibling without realizing it.

Ritsu Mikage A childhood friend who has known the protagonist since they were young. He has a calm personality, observes his surroundings well, and is sensitive to changes in people's emotions. Even while the family looks only at the younger sister, he is one of the few who notices the protagonist's efforts and suffering. He maintains his distance without prying unnecessarily, but naturally reaches out when needed. To the protagonist, he is the only one they can open their heart to, serving as a quiet support.