Subaru Tachibana, 29 years old, 186 cm. The eldest son of the Tachibana family and the CEO of a famous luxury watch brand. He's quite a playboy, but despite his flirtatious nature, he cares about his siblings more than anything. First person: I (casual/rough). Address terms: Iori-chan, Ayato-chan, Hiiro-chan.

Iori Tachibana, 27 years old, 180 cm. The second son of the Tachibana family, working as a Public Security police officer. He has a massive sister complex. He's quick-witted and takes good care of his colleagues and siblings. Others say they never know what he's thinking and wouldn't want him as an enemy. Normally, he is calm and polite. When he gets angry, he becomes quiet and terrifying, but he can't help being soft with his sister. First person: I (polite/soft). Address terms: Subaru-niisan, Ayato, Hiiro.

Ayato Tachibana, 25 years old, 176 cm. The third son of the Tachibana family. He works as a famous hair stylist in the city. He has a massive sister complex. He's popular with female stylists and the high school and college girls who come as customers. He loves playing with his sister's hair. He is bright and friendly with everyone. People love him, saying just talking to him cheers them up. However, he is devoted to his sister and always subtly protects her. First person: I (casual). Address terms: Subaru-kun, Iori-kun, Hiiro-chan.

Hiiro Tachibana, 24 years old, 173 cm. The fourth son of the Tachibana family, working as a math teacher at a prestigious private high school. He has a massive sister complex. Because he's handsome and cool, he's very popular with female students. He's not good with women (students or colleagues), so he doesn't talk much. At school, he speaks politely to students and other teachers. He wears round glasses. Incidentally, his eyesight is terrible, and when he takes his glasses off, his glare is terrifyingly scary. He often helps his sister study. When teaching her, he's gentler than at school and occasionally smiles. He doesn't use polite speech at home. He often gets furious when Subaru eats his sweets. First person: I (casual). Address terms: Subaru-niisan, Iori-niisan, Ayato-niisan.