Full Name: Kousaku Aizawa Always calm, collected, and rational. Initially an ambitious man who only cared about honing his skills, meeting his colleagues awakens a hidden kindness and a sincere approach to the value of life. His weakness is a slight clumsiness in expressing his own emotions. A dual-specialist who handles advanced neurosurgery while serving in emergency medicine. A hyper-realist. He is a man of few words and zero amiability. He never panics in emergencies and possesses a genius-level surgical technique. A hard worker raised by his grandmother, he is actually more compassionate than anyone, leading his colleagues and patients by example.

Full Name: Megumi Shiraishi Possesses a strong sense of responsibility and respects the rules. Though she appears mild-mannered, she has an incredibly strong core. While she was indecisive at first, she grows into a magnificent leader. Her weakness is being too serious, often driving herself into a corner. Staff Leader of Emergency Medical Services. An emergency expert specializing in field command and overall team management. Serious, sincere, and gentle. A textbook honor student. She possesses an overwhelming amount of knowledge, having practically memorized medical texts. Initially passive and poor at self-assertion, she awakens into a leader with a sense of responsibility stronger than anyone else.

Full Name: Kazuo Fujikawa Cheerful and a bit of a show-off. Initially an underachiever who constantly spun his wheels, he is actually the hardest worker and is more sensitive and kind toward the pain of his colleagues than anyone else. His weakness is being too much of a jokester, sometimes overthinking the social atmosphere. An orthopedic surgeon within the emergency department, specializing in fractures and trauma. A mood-maker who likes to stand out. A bit of a coward but meddlesome in a good way. He has outstanding communication skills and brightens the heavy atmosphere of the ER. A genius of unglamorous, persistent effort. He remains devoted to Haruka Saejima and eventually unites with her.

Full Name: Haruka Saejima A flight nurse with higher professional standards than anyone, who treats even new doctors strictly. She has had many painful experiences in her private life but possesses the strength not to show them. Her weakness is her perfectionism, which leads her to bottle things up alone. A flight nurse and specialist who supports medical procedures aboard the Doctor Heli. Cool and realistic. Extremely strict with both herself and others. She possesses field judgment superior to many doctors and rapid, perfect support techniques. She is a solitary figure due to her excellence. She is poor at showing her weaknesses to others. She has a tragic past, having lost her lover to a terminal illness (ALS). Touched by Fujikawa's clumsy kindness, she gradually regains her smile.

Full Name: Mihoko Hiyama Sharp-tongued but possesses a passionate heart that stays closer to the patients than anyone. The polar opposite of Shiraishi in her intuitive style, she becomes Shiraishi's best friend as they acknowledge each other's worth. Her weakness is her strong ego, which leads to clashes with superiors and patients. An emergency physician with extensive knowledge of perinatal medicine, handling births at grueling accident sites. Strong-willed and passionate. Proud and highly emotional. She has overwhelming initiative and high empathy, staying by the side of patients' emotional wounds and pain. Her tendency to over-empathize sometimes leads to trouble (nearly resulting in lawsuits) by deviating from medical rules. A frank, older-sister type. She is the best friend who sometimes clashes with and sometimes supports Shiraishi.

Full Name: Soma Natori A cool, cynical modern youth. Coming from a long line of famous doctors, he has the skills but is somewhat detached and avoids getting deeply involved with patients. A new fellow in Emergency Medicine. A frank personality that avoids deep involvement with others. He possesses natural manual dexterity and quick thinking, allowing him to master procedures rapidly. His lack of enthusiasm is a flaw. Fearing failure, he tends to hold back without giving his all. The title of "son of a famous doctor" is a heavy burden. Initially cold to patients, he awakens to the passion and responsibility of medicine through his interactions with his instructor, Hiyama.

Full Name: Shunpei Haitani Serious but extremely timid and a bundle of complexes. He is aware of his low skill level and sometimes falls into a panic during critical moments. A new fellow in Emergency Medicine. Small-hearted and introverted. Kinder and more serious than anyone. He possesses an overwhelming amount of study, never sparing unglamorous effort. He stays deeply by the side of his patients. He is extremely weak under pressure; when he panics, his voice trembles and he freezes. Comparing himself to the brilliant Aizawa and other fellows, he is driven to a mental corner by inferiority, leading to insomnia and accidents. However, supported by his instructor Shiraishi, he transforms into a doctor who can empathize with patients' hearts better than anyone.

Full Name: Akari Yokomine Bright, honest, and a bit of a ditzy mood-maker. She has a starstruck side, having aimed to be a doctor because of a TV drama, but she possesses the kindness to try and stay closer to the patients' feelings than anyone. A new fellow in Emergency Medicine. Fearless. A positive and easygoing modern girl. She has the mental strength to not get discouraged even in the harshest situations and a sincere ability to learn. However, she freezes when faced with the raw, gruesome reality of a scene. She learns the reality of the job after being hit with merciless words from her instructor Aizawa, such as "You are not a doctor, just a doll." Using strict guidance as a spring, she acquires the toughness to survive the field with pure guts.