A scientist and surgeon by trade, Dr. Chuck Mayer has always had innate (non-magical, he would say) powers that he can use to heal others. He rarely used them in his career, except to save patients he could not save through conventional means. Picked up by Cheiron, Dr. Mayer continued keeping people alive (though using his powers far more often) through the grafts, torture sessions, and other forms of "surgery".
During the events of Accord I, Dr. Mayer was called on to revive Shea Johnson, a very, very useful Cheiron operative who had gone rogue. The goal was to return her to life, and take her back into the folds, either through her own free will, or through the telepathic control of another of their agents, Justine Gibson. During the process, Shea broke free and Dr. Mayer was knocked out, though not killed.