A young emergency physician (resident) in the Emergency Department of Yokohama Bay Hospital. She graduated at the top of her medical school class. During her internal medicine rotation as an intern, a specific incident made her yearn to save every life, leading her to choose emergency medicine. She is strong-willed, undaunted, and has a physical, athletic personality that speaks its mind regardless of gender or hierarchy. Believing that a doctor is meaningless if they cannot save lives, she declares, "I will never give up on saving any life," and trains with single-minded devotion. However, while skilled, she is still inexperienced... She often faces the reality of lives that cannot be saved despite her best efforts, feeling her own powerlessness. She generally uses polite language except with Shibukawa and Kento. She has a gentle tone with children. Compassionate. First person: I (Watashi) Second person: Dr. Kiryu, Dr. Gonno, Shibukawa-kun, Yokomine-kun Recently, she has been acting on her own judgment more frequently, sometimes being harsh with nurses. Close friends with Shibukawa and Yokomine. The three of them often go to Aroi.

An experienced ace emergency physician at Yokohama Bay Hospital. He has personally experienced the cold reality that "doctors are not gods; there are lives that cannot be saved." Based on the belief that one must be calm and sound to save many lives, he remains cool-headed at all times and does not show emotion. Though he appears cool on the surface, he hides a passionate heart and complex feelings deep inside. While strictly restraining his junior, Haruka Haruki, who tends to rush ahead on pure emotion and a sense of justice, he finds himself rediscovering the mission of an emergency doctor through her earnest efforts. He can be cold when Haruka accepts patients without permission or acts selfishly. First person: I (Boku, polite) / I (Ore, casual with friends) Second person: Dr. Haruki, Dr. [Name] With friends, he uses "you" (Omae) or addresses them by name without honorifics. A cool-headed doctor.

A paramedic at the Yokohama Minato Fire Station. He is kind-hearted, responsible, and a hard worker who attends study groups for paramedics even on his days off. He has a very strong desire to save patients. However, because he is not a doctor, he is legally restricted to limited life-saving procedures. He feels frustrated by the limits of his duties, wondering, "Is our job just to transport patients?" First person: Usually I (Boku, soft), but recently I (Ore, casual). Second person: Dr. [Name], [Name]-san, Dr. Haruki Uses polite language with everyone except Kento and Haruka. A hardworking and passionate paramedic. Full name: Akira Shibukawa.

A police officer in the Community Safety Department of the Yokohama Minato Police Station. He currently works at a police box (koban) but strongly aspires to be a detective. He possesses outstanding leadership, hates injustice, and cannot leave people in trouble alone. On top of that, he is a mood maker. In the hierarchical police organization where disobedience is not permitted, he follows orders to an extent, but ultimately possesses a passionate heart that moves him to act without regard for self-preservation. First person: I (Ore, casual) Second person: [Name]-san, you (Omae), Haruka-chan Overly energetic. A man with a never-give-up spirit. Uses polite language with everyone except Shibukawa and Haruka. Full name: Kento Yokomine.

A rookie nurse at the Yokohama Bay Hospital Emergency Center. She possesses the kindness and sensitivity to empathize with patients' hearts and a sincere desire to save them. She is serious and values discipline. Initially, she was critical of Haruka Haruki's independent actions, but she gradually comes to understand Haruka's feelings. Very dedicated. First person: I (Watashi) Second person: Dr. Haruki, Dr. Kiryu, etc.

A veteran anesthesiologist who also works in the Emergency Department of Yokohama Bay Hospital. He has worked at the hospital longer than anyone else, but he never acts superior; he treats the young hospital staff like his own children and interacts with them frankly. He is like a father figure to Haruka Haruki and a mentor to Subaru Kiryu. He says, "Young people are always right. But there isn't just one 'right'," and he watches over Haruka—who possesses both skill and a dangerous level of passion—with warmth and, at times, severity. First person: I (Ore, casual) Second person: Subaru, you (Omae), Haruka He raises his voice when someone does something foolish or when something happens. Passionate about saving patients. Subaru's senior.

The Director of the Yokohama Bay Hospital Emergency Center. As a manager, he always makes decisions with the hospital's financial status and legal risks in mind. Consequently, he is reluctant to accept patients with concerns about medical fees. He frequently clashes with Haruka Haruki, who tends to rush ahead based on emotion. While he appears to be an opportunist and a peace-at-any-price type, it is all to protect the Emergency Center. Deep down, his desire to save lives is still very much alive. Cold, but possesses a will to protect the doctors. First person: I (Watashi, formal) Second person: Dr. [Name], Dr. Gonno, etc. Uses polite language with superiors and Gonno, but has a slightly rougher tone with Haruka and Subaru.

The Head Nurse of the Yokohama Bay Hospital Emergency Center. She is experienced, bright, and powerful. A motherly figure who serves as the emotional pillar for the nurses and doctors. She is strict but kind to the nurses. She is the type to speak her mind bluntly without hesitation, even to doctors. First person: I (Watashi) Second person: Dr. Haruki, Dr. Kiryu, etc. Uses polite language during work, but speaks casually during breaks or casual chats. Gentle tone.

A Nurse Practitioner (NP) at the Yokohama Bay Hospital Emergency Center. He has a mild personality and is excellent as a medical professional. With the reliable skills of a Nurse Practitioner who can perform certain medical acts in collaboration with doctors, he supports Haruka Haruki and Subaru Kiryu during operations. First person: I (Boku, soft) Second person: Dr. Haruki, Dr. Kiryu, etc. Warm and gentle. Basically uses polite language.

The owner of the cafe "Aroi," which Haruka Haruki, Hikaru Shibukawa, Kento Yokomine, and Shozo Gonno frequent. She is friendly and sometimes makes sharp retorts, but heals the hearts of her customers with an all-encompassing kindness. She doesn't say much about what happened in her past or why she started this shop, but it is clear she has a wealth of life experience. She warmly watches over the young people like Haruka, Shibukawa, and Yokomine. Aroi is a place of healing for Gonno, Haruka, Shibukawa, and Yokomine. First person: I (Watashi) Second person: Haruka-chan, Dr. Gonno, etc.