Ophiuchus

Ophiuchus was a Time Lord healer whose work allowed their people to overcome the regeneration cycle's limit of thirteen lives.

Biography
The Doctor knew Ophiuchus as a noble healer and the head of his order. Seeking to help those whose lives ended prematurely, Ophiuchus used a metamorphic symbiosis regenerator to tap into his regenerative energy.

Upon learning of Ophiuchus' work, the High Council of Gallifrey declared him a renegade. Claiming Ophiuchus to have committed "terrible crimes" such as vivisection as a means to extend the life of Gallifreyan criminals, the High Council sent the Chancellery Guard to kill him. Believing that the Council would take his research for their own purposes, Ophiuchus eluded his pursuers by taking refuge in the Cloisters beneath the Capitol, in an area hidden by a simple holographic projection.

Fortunately for Ophiuchus, he was confronted by the Fifth Doctor, accompanied by companions Nyssa, Tegan Jovanka and Vislor Turlough. It soon became apparent that Ophiuchus was dying, and he requested that the Doctor give him the "little push" needed to save him. Ophiuchus revealed that, by channelling the energy in the containment chamber through his body, it would use his biometrics as a blueprint and duplicate his regenerative energy signature.

Convinced by Nyssa and Tegan, the Doctor complied and saved Ophiuchus' life, allowing him to regenerate into a female form. Placing his trust in Ophiuchus' character, the Doctor advised her to leave Gallifrey while he would claim to the High Council that she was destroyed by her experiments. Leaving in her TARDIS, Ophiuchus suggested that her gift could help the Doctor one day. (COMIC: Ophiuchus)

Legacy
Ophiuchus' prediction regarding the Doctor would come to pass at the conclusion of the Siege of Trenzalore, when Clara Oswald convinced the Time Lords to enable the Eleventh Doctor, who was on the brink of dying of old age with his regenerations expended, escape his death on the planet Trenzalore by providing additional regeneration energy to him, resulting in him regenerating to the Twelfth Doctor and beyond. (TV: The Time of the Doctor, COMIC: The Many Lives of Doctor Who)