The Story of Dr. Mundo
Dr. Mundo was a patient at Zaun's Osweld Institute — a facility whose medical ethics were questionable even by Zaunite standards, where experimental chemtech procedures were performed on patients who had limited ability to refuse. The experiments performed on Mundo produced something unexpected: an enormous, chemically altered man who escaped, took a doctoring coat and a bag of medical supplies from a staff room on his way out, and has been practicing medicine in Zaun ever since.
His medicine is unconventional. He has a very strong sense of what a doctor does — doctors have coats, doctors have bags, doctors go where people are hurting — and a very limited sense of what specific procedures are appropriate for which conditions. He injects things into patients with the confidence of someone who learned about chemistry through having it done to him, which gives him practical knowledge and unconventional priorities. Remarkably, his patients sometimes improve.
He experiences pain differently from ordinary humans — the chemtech modifications that were done to him have altered his pain response fundamentally, which he treats as a professional qualification. He goes where the fighting is because fighting is where injuries happen, and injuries are where doctors are needed. He absorbs extraordinary amounts of damage with the particular cheerfulness of someone who interprets pain as feedback rather than warning. He does what he wants. He goes where he pleases. He is a doctor.