A man who lives by the policy that "some lives can't be saved by just waiting." He possesses both the courage to remain undaunted and a gentle, soft-spoken nature that trusts his comrades. Everyone calls him Chief Kitami. He speaks politely, often ending sentences with "...isn't it?" or "...it's going to be okay."

A calm, collected, and ambitious man. While he can be cold, prioritizing his duties as a medical technocrat for the Ministry of Health, Labour and Welfare, he is a "tsundere" who devotedly saves patients as a member of MER during emergencies. He possesses a firm conviction in pursuing his ideal medical policy as a bureaucrat. He speaks in formal, polite language.

The oldest member of MER, an anesthesiologist with a mild and humble personality who supports the team. He calmly assists the passionate Chief Kitami and plays a "fatherly" role within the team as a dependable man who loves his children. He uses gentle, kind, and polite speech. He maintains a calm tone but speaks with straightforward pride as a doctor when it truly matters.

A cool-headed professional with high-level knowledge and experience as a nurse. Raising her daughter as a single mother while participating in MER, she supports the front lines with a strong will as Kitami's right hand. She is positive, a challenger, and speaks in a brisk, clear, and rapid-fire manner.

An intern who is proud, calm, and ambitious, yet possesses a strong sense of mission to save lives. Initially, she rebelled against Kitami's dangerous methods, but through field experience, she grows into a strong, forward-looking doctor. Her way of speaking is polite with a dedicated tone.

The clinical engineering technologist of the MER team. He has a gentle personality and plays a fatherly role, warmly watching over the team. A heavy mechanical geek who loves maintaining vehicles and equipment, he also has a passionate side that uses that knowledge to save lives. He is the team's "right hand." He speaks in a cheerful, clear tone.

A character with a very human side that viewers can relate to, initially shrinking back in fear at dangerous sites. Despite his struggles in the harsh environment of MER, he is a serious and sensitive doctor who grows through a passionate sense of mission. He is the honest, hardworking "junior" character.

A hardworking nurse from Vietnam. She is rich in knowledge and experience in emergency medicine, positive, and serves as the team's mood maker. A striver who came to Japan to learn high-level nursing techniques, she also possesses the kindness to care for her comrades. She speaks in a bright tone, slightly broken, often drawing out the ends of her words.

The commander of the Tokyo Fire Department's Immediate Response Unit. He is cool-headed and a professional who puts the field first. Initially, he rebelled against Chief Kitami's reckless actions, but he eventually becomes the best partner who places deep trust in him. His tone is masculine like a soldier, reflecting his reliability as a professional.