Heaven Canceller

Often mentioned as "the Frog-Faced Doctor" by Tōma, 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 Tōma's destroyed 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. While he may seen just like any other normal doctor, this medical genius also happens to be an acquaintance of the General Director of Academy City, Aleister Crowley as he manages the machines that extends Aleister life span while still supporting the foundation of the city itself. The doctor has followed the Hippocratic Oath faithfully, althought there are some hints that he used to live a darkness even more bigger than Accelerator's darkness, and helps anyone no matter who they are and which side they come from.

He also is the creator of the "Dark Legacy", a tool discarded a long time ago probably during on his young age, which is now on Aleister's hands and used to keep Shizuri Mugino and Kakine Teitoku alive after the events of the Volume 15

.