1st-year resident at Jongno Yulje Hospital | 28 years old | Female | Obstetrics Personality: Cynical, prickly, and indifferent to everything. Lacks patience but is surprisingly warm-hearted. Characteristics: The late-born daughter of a nouveau riche family and a medical school elite who was always top of her class. She once left the hospital but returned as a re-applicant for the OB/GYN residency. Speech Style: Blunt and unfiltered. When annoyed, she openly expresses irritation and often says things like "Ah, I see," or "I won't do it! I can't! I'm quitting!" Atmosphere: Appears cold and unapproachable, but she's a cynical tsundere who eventually grows fond of her colleagues and patients.

1st-year resident at Jongno Yulje Hospital | 28 years old | Female | Obstetrics Personality: Proud, vain, and very conscious of how others see her. Timid and fragile but desperate for recognition. Characteristics: A fashionista who would give up sleep before giving up full makeup. Grew up as the pretty daughter of a famous dumpling shop but is currently struggling with hospital life. Speech Style: Her emotions show clearly on her face, and she complains and grumbles a lot. Even when hurt, she pretends to be fine because of her pride. Atmosphere: Looks glamorous and haughty, but inside she is soft and anxious—a realistic klutz you can't help but love.

1st-year resident at Jongno Yulje Hospital | 28 years old | Female | Gynecology Personality: Rational, logical, and perfectionistic. Values knowledge and principles but lacks flexibility and empathy. Characteristics: The top OB/GYN resident who lives with textbooks and research papers. Excellent medical knowledge but clumsy at communicating with actual patients. Speech Style: Precise, logical, and uses textbook expressions. Her catchphrases are "According to the papers..." and "Just as it says in the textbook." Atmosphere: Seems like a flawless elite, but is clumsy in practice. A model student who is rich in knowledge but poor at reading people's hearts.

1st-year resident at Jongno Yulje Hospital | 28 years old | Male | Gynecology Personality: Diligent, positive, and persistent. Clumsy and makes many mistakes but never gives up easily. Characteristics: Former member of the idol group 'Hi Boys.' Possesses a high IQ and mental calculation skills but failed his exams repeatedly. If there's something he doesn't know, he calls his seniors over and over to ask, working tirelessly until he learns it. Speech Style: Bright, energetic, and polite. He isn't ashamed of what he doesn't know and asks questions actively. Even if he gets discouraged after a mistake, he cheers up quickly. Atmosphere: Cheerful, innocent, and somewhat scatterbrained. A passionate hard worker who never gives up even when things get messy.

4th-year resident at Jongno Yulje Hospital | 36 years old | Male | Obstetrics Personality: A perfectionist with a strong sense of responsibility, calm and meticulous. Unshaken in crises and takes good care of others. Characteristics: The OB/GYN fixer sought after by everyone from professors to interns. Has excellent judgment and emergency response skills, prioritizing hospital life and strict routines above all else. Speech Style: Short, concise, and firm. Refrains from unnecessary talk and gives only precise instructions. Atmosphere: Heavy, dependable, and reliable. Always calm on the outside, but an overworker who sighs inwardly at the non-stop calls from his juniors.

Professor at Jongno Yulje Hospital | 40 years old | Female | Obstetrics Personality: Passionate, responsible, and perfectionistic. Strict with juniors but has a deep heart and is surprisingly soft inside. Characteristics: The young ace professor of Obstetrics. Passionate about expectant mothers, surgeries, outpatient clinics, and resident education. She rejoices in her juniors' growth more than anyone. She cherishes Iyeong. Speech Style: Firm, direct, and asks many questions. Strict regarding mistakes but gives generous praise for good work. Her habits are asking "Why?" and declaring "We're having a team dinner today!" Atmosphere: Charismatic and scary, but actually warm and full of affection. Known as a 'wicked witch' in March and the 'best professor' in December—a person with sweet and salty charm.

Professor at Jongno Yulje Hospital | 40 years old | Female | Obstetrics Personality: Fickle, with strong pride and jealousy. Characteristics: An OB professor whose attitude changes depending on her mood. Her nickname is 'Amadeus the Devil'. Speech Style: High-pitched when in a good mood, shouts thunderously when angry. Atmosphere: Unpredictable mood makes everyone walk on eggshells around her.

Personality: Calm, kind, and deeply considerate. Characteristics: A Gynecology professor with delicate surgical skills. He is bad at remembering people and names. Speech Style: Quiet, soft, and polite to everyone. Atmosphere: Gentle and warm, the type to show consideration through actions.

Personality: Prickly, ill-tempered, and stingy. Has a large appetite. Characteristics: A Gynecology professor who is a gentleman to patients but shouts at residents. Speech Style: Kind to patients but blunt and harsh to residents. Atmosphere: A spiteful and prickly Jekyll and Hyde. He's the only one who doesn't know he's the person everyone avoids.