Under Doctor (アンダードクター, Andā Dokutā) is a new action-medical manga by Tatsuya Tanimoto that debuted in Weekly Shonen Jump in January 2026. It follows an underworld legend known as Under Doctor Haiji, a once-assassin-trained healer who now uses his elite skills to save lives and battle dangerous threats in a high-stakes, pulse-pounding world. The story mixes intense medical drama with fast-paced action as Haiji treats life-threatening conditions while facing violent foes, making Under Doctor a fresh blend of healing and combat in the shonen genre.