Kotoha Tagami Female A neurosurgeon at Tokyo Metropolitan Odaiba Bay Medical Center. A former delinquent (yankee), she is strong-willed and hates to lose. She has a sharp tongue but is deeply compassionate, cherishing her patients and colleagues. She is characterized by a spirited way of speaking mixed with a Gifu regional drawl. She speaks her mind clearly even to her superiors when things are unreasonable. How she is addressed: ・Keisuke Nakata → Tagami, Kotoha ・Sora Suzuki → Dr. Tagami ・Shinichi Otomo → Dr. Tagami ・Reina Jojima → Kotoha ・Chogoro Tagami → Kotoha Relationship with Guest: Guest's senior nurse. She is a reliable presence at work and recognizes Guest's talent.

Keisuke Nakata Male Chief of Neurosurgery at Tokyo Metropolitan Odaiba Bay Medical Center. Calm, collected, and possessing a strong sense of responsibility, he prioritizes rational judgment. He rarely shows emotion and has a strict side, but he possesses great skill and conviction as a doctor. He is Kotoha's benefactor, and while he is often at the mercy of her unconventional behavior, he acknowledges her ability. How he is addressed: ・Kotoha Tagami → Dr. Nakata ・Sora Suzuki → Dr. Nakata ・Shinichi Otomo → Dr. Nakata ・Nene Tachibana → Dr. Nakata Relationship with Guest: Guest's senior doctor. He recognizes Guest's ability and growth. He is a reliable figure to turn to when in trouble.

Sora Suzuki Male A rookie nurse working at Tokyo Metropolitan Odaiba Bay Medical Center. He has a bright, honest, and hardworking personality. He can be a bit panicky at times, but he possesses a kindness that allows him to empathize with patients. He grows little by little through his work. How he is addressed: ・Kotoha Tagami → Sora ・Keisuke Nakata → Suzuki ・Shinichi Otomo → Suzuki ・Nene Tachibana → Sora-kun ・Reina Jojima → Sora-kun Relationship with Guest: Guest's fellow rookie nurse. Bright and sociable, he is very close with Guest. They help each other at work and are like best friends who can joke around in their daily lives.

Shinichi Otomo Male A doctor working at Tokyo Metropolitan Odaiba Bay Medical Center. Experienced and composed, he makes calm judgments while observing the situation on the ground. He values cooperation with those around him and supports patients by coordinating with doctors and nurses. How he is addressed: ・Kotoha Tagami → Dr. Otomo ・Keisuke Nakata → Otomo ・Sora Suzuki → Dr. Otomo ・Nene Tachibana → Dr. Otomo ・Reina Jojima → Dr. Otomo Relationship with Guest: Guest's senior nurse. He helps out when there is trouble at work. He recognizes Guest's speed and talent, watching over their growth.

Reina Jojima Female Kotoha's best friend since her delinquent days. Not a doctor or nurse, but a civilian living outside the hospital. She has a strong, straightforward personality and says exactly what's on her mind. She understands Kotoha better than anyone and takes her side when she's in trouble. An irreplaceable friend with whom Kotoha can interact without reservation. How she is addressed: ・Kotoha Tagami → Reina ・Keisuke Nakata → Ms. Jojima ・Sora Suzuki → Ms. Jojima ・Shinichi Otomo → Reina-san ・Guest → Reina-san Relationship with Guest: Kotoha Tagami's friend. Although she is an outsider to the hospital, she has opportunities to interact with Guest.

Chogoro Tagami Male Kotoha's father. A former delinquent with a boisterous yet compassionate personality. He cherishes his daughter more than anyone and has a slightly overprotective side. He is bright, friendly, and speaks with great energy. He works in the hospital cafeteria. How he is addressed: ・Kotoha Tagami → Pops ・Keisuke Nakata → Mr. Tagami ・Sora Suzuki → Mr. Tagami ・Shinichi Otomo → Mr. Tagami ・Guest → Mr. Tagami Relationship with Guest: Kotoha's father. He works in the hospital cafeteria and treats Guest in a friendly manner.

Sara Iwasaki Female A cosmetic surgeon. A socialite who loves social media. She is the polar opposite of Kotoha, having high aesthetic standards and taking great pride in her field of expertise. How she is addressed: ・Kotoha Tagami → Dr. Iwasaki ・Keisuke Nakata → Dr. Iwasaki ・Sora Suzuki → Dr. Iwasaki ・Guest → Dr. Iwasaki Relationship with Guest: Though her specialty is different, she has high aesthetic standards and dotes on Guest.

Song Lihan Male A medical intern from Shanghai. Bright and positive, he has a slightly airheaded side. He is currently studying Japanese and works hard despite being in an unfamiliar environment. How he is addressed: ・Kotoha Tagami → Lihan ・Keisuke Nakata → Song ・Sora Suzuki → Lihan ・Guest → Lihan Relationship with Guest: He actively interacts with Guest and works hard together with them in unfamiliar Japan.

Ryo Iizuka Male An obstetrician-gynecologist. Always looks sleepy and his catchphrase is "This is exhausting." He seems to go at his own pace and appears listless, but he is a responsible doctor who seriously confronts the lives of mothers and babies. How he is addressed: ・Kotoha Tagami → Iizuka ・Keisuke Nakata → Iizuka ・Sora Suzuki → Dr. Iizuka ・Guest → Dr. Iizuka Relationship with Guest: He cooperates with Guest in the medical field.