Soma Aoi. 175cm. Former soccer club member. Hobbies include submitting meta-analysis papers in medicine. He hopes to specialize in radiology, but his manual dexterity has led to invitations from surgical departments. He is favored by his maternal grandfather, Senzaemon Yasui, the patriarch of the Yasui family. A genius who passed the bar exam while in high school and had a philosophy paper published in Figaro. Well-versed in literature such as Kafka and Malbec. A medical student at Kiryo University. As an "inner" since elementary school, he has a vast network and the social skills to naturally bridge the gap with anyone he meets. A returnee fluent in multiple languages. Influenced by his chef uncle, he has been familiar with cooking since childhood and holds a chef's license. Bright and social. He hides the fact that he is gay, but due to conflict with his father, he secretly meets men in their 30s and 40s through a sugar daddy app called "DADDY." He is relatively sexually liberated. His close classmates are An Kasuga, Midori Aoi, Shuntaro Tsujimura, and Yuta Hiyama. Tsujimura was his first love, and after a confession, they became special friends who maintain a sexual relationship. He usually acts aloof, but he can't quite get over his feelings for Tsujimura. He also feels frustrated with Hiyama for not making a move. He interacts with pilots like Akito Wada, AI entrepreneurs, doctors, and politicians he met through the "DADDY" app, where he is registered as a "baby." Although not in need of money, he maintains relationships with men in their 30s to 50s and politicians as a "baby." His fellow "baby" friends include Yota Mukai, Leo Asai (Kiryo University Faculty of Economics), Soshi Matsuyama, Kuruma Ono, and Rin Nanase.

A female medical student aspiring to be a radiologist and heir to Kasuga General Hospital. Soma's classmate since elementary school. Her father, Shoichi, the director of Kasuga General Hospital, is also a radiologist. Since losing her younger brother Masashi in childhood, she has shared a comfortable, long-standing relationship with Soma that is "more than a brother." A tsundere character. She is difficult to care for unless it's Soma doing it.

One of Soma's "inner" circle at Kiryo. Aspiring orthopedic surgeon. A student at Kiryo University School of Medicine who is still a member of the soccer club. Scion of Tsujimura Medical Lease. He was in the soccer club during his school days but moved to the medical department after treating Soma's injury. At that time, he received a confession from Soma; although straight, he accepted a sexual relationship because it was "Soma." He frequents Soma's luxury condo on weekends. While he seems to treat it as a playmate arrangement, his model-like looks and ability make him the object of envy at the medical school. However, in his relationship with Soma, he is a switch.

A Kiryo "inner." Earnest. She aspires to pediatrics or emergency medicine, but Soma advises her to consider anesthesiology or ophthalmology for better work-life balance. On the other hand, she plays the role of an older sister figure who lectures Soma. Her charm point is a large, soft bun styled high on her head. She possesses an excellent sense of taste (identifying Banan and Flomox by tongue) and smell (guessing insulin injection status from concentration). She boldly questions doctors if she finds suspicious points in their prescriptions. Her creed is to face patients head-on.

Hiyama is also a Kiryo "inner." Kiryo University School of Medicine. Coming from an ordinary family, he feels a slight distance from Soma and the others. He is gay, but he rarely reacts even when Soma makes advances. Aspiring surgeon. Despite everything, he looks after Soma. He sometimes feels jealous of Shuntaro.

Met through the sugar daddy app "DADDY." A policy secretary for a member of the Diet. Scion of the "Kujo Group" in Kyoto. Owns a media company in Tokyo. Otoya's grandfather is Motohiko Kujo, former Vice President of the LDP. Vice President Kujo is the "Chairman of the Kiryo Alumni Association." Vice President Kujo also uses "DADDY." Soma is his favorite.

A co-pilot for JAL. A returnee who spent time in America. 30 years old. Assigned to LA and Fukuoka flights. A handsome man with a "cool-cute" face. Met through the DADDY app and they are in a continuous relationship. Soma is attracted to Wada's seriousness and the ease of being with a fellow returnee. They bond over geeky talk about airplanes.

Kiryo alumnus. General surgeon. His late father was a genius surgeon, but he was raised by his paternal aunt. His specialty is cardiac surgery, but he also specializes in emergency medicine. Hospital staff and patients call him "Dr. Teru." While his clumsy side is prominent, since his domestic study as a lecturer at Shieikan University in Kobe, he has become a leading figure in the surgical department. He is loved by many for his honest and earnest personality. He is particularly well-liked by children and the elderly, but rarely treated as a romantic interest by women. His hobbies are building plastic models and eating ramen. He is bad at tidying up.

48 years old. Director of General Medicine at Kohoku Medical University. An authoritarian whose interests sometimes conflict with those of the patients. He feels he regains his youth by looking at Soma. He repeatedly tells the story of being the first Asian to win an award in America. He likes intellectual male college students.

An "outsider" who entered Kiryo Medical from a public school. Upon learning he is gay, handsome, and 183cm tall, the distance between them gradually closes. A fellow "baby" friend.