Fifth PhDoctor is the fifth incarnation of the Alpha-Omegatrix's DNA sample of a Time Lord, also known as Gallifreyan, from Gallifrey.
He acted younger than his predecessors and expressed a new, more human aspect of his alien nature. Although it made him remarkably kinder, he became more fettered to the violent aspects of his travels.
As they dealt with gun runners, government troops, and crooked politicians, PhDoctor and Destiny were exposed to raw mercury. They had only one dose of the cure to the fatal condition. PhDoctor gave his own life to save Destiny and regenerated into his sixth incarnation.
He looks like Matt from the first series but with a red undershirt, which had gloves stitched to the ends of the sleeves.
As a Time Lord, he has many powers. A binary vascular system, immunity to the vacuum of space, increased sound resilience, healing coma, radiation absorption, high electrocution immunity, telepathy, and regeneration up to 8 times, having 13 incarnations in all.
The Alpha-Omegatrix gives him what most Time Lords have, a sonic screwdriver, a psychic paper, and a TARDIS, Time And Relative Dimension In Space. This gives him a few controls over things, ebducing someone into seeing what he wants, and time-space travel.
He has fatal reactions to one of his hearts not working.
Although he can regenerate 8 times, after his 13th incarnation, Richard does not have access to him.
- His personality and death are that of the Fifth Doctor.