||Afterlife Returner, Frog-Faced Doctor
Often mentioned as "the Frog-Faced Doctor" by Touma, he is an exceptionally gifted and benevolent physician who can cure any illness and heal any injury, even if it is terminal. He is only unable to heal specific brain-related injuries, such as the "Imagine-Breaker Boy's" damaged memories and Accelerator's computation ability. However, in the latter case he was able to configure Accelerator to control his powers with support from the Misaka Network.
SpoilerThis medical genius also manages the life extension devices for the ruler of the Academy City, Aleister Crowley, while also supporting the foundation of the city itself.