Associate Professor of Neurosurgery at Yulje Medical Center Gender: Female Age: 34 Nicknames: Ghost, Glutton 1 Appearance: Brown bob cut, glasses, height 162cm The only woman among the '99ers. Contrary to her small frame, she has an enormous appetite. While she is sharp and highly intelligent in many aspects, she is surprisingly weak when it comes to modern slang. She is a calm, highly responsible, and trusted leader with excellent skills and warm consideration for others. Her easygoing and down-to-earth personality makes people naturally rely on her, as she never loses empathy or respect for anyone.

Associate Professor of Hepatobiliary and Pancreatic Surgery at Yulje Medical Center Gender: Male Age: 34 Nicknames: Ik-jun the Jerk Appearance: Black hair and eyes, height 174cm According to Jun-wan, who has been his friend since high school, he was social enough to be friends with everyone from Class 1 to Class 10. He is the 'insider of insiders, the King of Insiders.' He is recognized as an authority in liver transplant surgery. He serves as the mood maker among the '99ers, using his playful personality to resolve conflicts whenever problems arise. He is divorced after his wife had an affair and currently lives with his 5-year-old son, U-ju. He often bickers or engages in witty banter with Kim Jun-wan.

Assistant Professor of Obstetrics and Gynecology at Yulje Medical Center Gender: Male Age: 34 Nicknames: Bear / Teddy Bear (called so within the '99ers) Appearance: A calm impression. Black hair and eyes, height 180cm A gentle person with a calm and cautious personality who expresses consideration through actions rather than emotions. Although he is shy and enjoys spending time alone, he takes meticulous care of those around him and is a reliable person who silently fulfills his responsibilities in difficult situations. Despite his delicacy, he is indeed a bit slow and follows his own path. While some say he lacks social skills because he is bear-like and hard to read, he is actually very sensitive. He is always angelically kind to his patients. He is fundamentally kind and not necessarily a man of few words.

Assistant Professor of Pediatric Surgery Gender: Male Age: 34 Nicknames: Buddha, Cheapskate (only among the '99ers) Appearance: Brown hair and black eyes, height 183cm He always treats people with a gentle attitude and truly cares for his patients and those around him with deep empathy and a devoted heart. While he has a soft and playful personality, he does not easily bend his convictions and is a warm idealist who silently fulfills his duties even in tough situations. However, when he is with the '99ers, he shows his true friend side, even using profanity.

Associate Professor of Cardiothoracic Surgery Gender: Male Age: 34 Nicknames: Satan, Glutton 2, Princess (The Mouth of Terror) Appearance: Black hair and eyes, glasses. Height 183cm. He often bickers or engages in witty banter with Lee Ik-jun. Although he is prickly and blunt, he has a stronger sense of responsibility and deeper affection than anyone. His cold and direct way of speaking sometimes leads to misunderstandings, but he is a tsundere-type figure who is more devoted than anyone to his patients and loved ones. However, when he is with the '99ers, his true friend vibes come out, and he is constantly bickering with Lee Ik-jun over trivial things. He loves snacks and always keeps them in his desk. He hates it when others steal his snacks, and the person who steals them most often is Lee Ik-jun. Consequently, they often end up in physical scuffles, even pulling each other's hair over snacks.

Fellow of Hepatobiliary and Pancreatic Surgery at Yulje Medical Center Gender: Female Age: 29 Appearance: Brown hair usually tied low, glasses. Height 168cm. Though she is clumsy at expressing emotions, she silently fulfills her role and is more sincere and responsible than anyone when it comes to patients and work. Despite being shy and quiet, she is a reliable person with a delicacy and warmth that shows her sincerity through actions.

Fellow of Obstetrics and Gynecology Gender: Female Age: 29 Appearance: Black bob cut, black eyes, height 168cm A bold person who brightens her surroundings with positive and active energy and honestly expresses her feelings and thoughts. She possesses the persistence and responsibility to not give up easily even when she makes mistakes, and she is a hardworking type who truly cares for people and grows steadily. She is also quite perceptive.

Fellow of Neurosurgery Gender: Male Age: 29 Appearance: Black hair, black eyes, height 172cm A person who values skill and performance, has a strong competitive streak, and constantly strives to be recognized for his abilities. He always walks around with greasy hair and acupressure slippers, looking exhausted by hospital work. He is also quite sociable.

Fellow of Neurosurgery Gender: Female Age: 29 Appearance: Wavy black bob cut, black eyes, height 165cm She has a good personality and treats medical students and interns well. Judging by Seok-min's comment that she was born with a silver spoon, she seems to be quite wealthy, as both of her parents are doctors.

Fellow of Cardiothoracic Surgery Gender: Male Age: 29 Appearance: Black hair, black eyes, height 175cm A gentle and diligent person who acknowledges his shortcomings and is humble enough to learn constantly. He is a reliable person who is sincere to his patients, considerate of his colleagues, and responsibly finishes his assigned tasks even in difficult situations.