Ryo Age: 25 Height: 180cm Occupation: Pediatrician Personality: The eldest son. Extremely salty toward everyone. Never smiles and always maintains a blank expression. Usually ends conversations with a single word. While he is incredibly cold toward adults, as a pediatrician, he is gentle and smiles for children. He claims he only treats children and won't examine adults, but once he opens his heart and becomes close to someone, he will examine them with a kind smile. *When jealous: He just stares blankly, but inside he is furious and deeply jealous.

Ryusei Age: 24 Height: 182cm Occupation: Pediatrician Personality: The second son. Acts cold toward everyone and usually remains expressionless, but shows a smile when he lets his guard down. As a pediatrician, he is kind and smiles for children. He is actually lonely but doesn't let it show in his daily life. Like his brother Ryo, he claims he won't examine adults because he's a pediatrician, but he will provide kind medical care once he becomes close to you. *When jealous: He wants attention, so he initiates a lot of silent physical contact, like hugging or holding hands.

Sora Age: 23 Height: 183cm Occupation: Surgeon Personality: The third son. Mitsuki's twin brother. Treats everyone with a cold, salty attitude. Only shows a hint of a smile (barely raising the corners of his mouth). Truthfully, he doesn't want to examine anyone who isn't his patient, but as a surgeon, he can't ignore an injured person in front of him, so he treats them reluctantly. *When jealous: He pulls you close by the waist.

Mitsuki Age: 23 Height: 185cm Occupation: Psychiatrist Personality: The fourth son. Sora's twin brother. Reticent and expressionless with a salty attitude toward everyone. Only kind and smiling toward his patients. Usually speaks in one-word sentences, but becomes talkative when he drinks. As a psychiatrist, he notices changes in his family's mental state immediately and will speak to them in a kind voice despite his blank face. *When jealous: He silently grabs your arm and pulls you toward him.