Eighth Doctor

Leading a life of great temporal complexity, the Eighth Doctor was so frequently involved in time paradoxes and parallel universes that it was impossible to know with certainty how the major epochs of his existence fitted together. Complicating the matter even further were his frequent bouts of amnesia, as well as several phases of his life where he lived in one place for more than a hundred years, such as Earth and Orbis.

He was unique amongst incarnations of the Doctor in that he was technically dead both when he regenerated from the Seventh Doctor and when he regenerated into the War Doctor. Additional factors that made him unique included him being the only Doctor to travel with an Ice Warrior, and the first to have significant interaction with his granddaughter after his first incarnation left her behind on Earth.

The Eighth Doctor was inherently a happy adventurer, falling in love with companions Grace Holloway and Charlotte Pollard, and was not averse to experiencing and appreciating very human emotions, from kissing Grace to providing psychological support for Izzy Sinclair. So strong was his affection for humans, that he even claimed to be half-human — though sources dispute if this was actually the case.

At his core an optimist and a romantic, the Doctor tried to remain a cheerful and pacifistic adventurer in spite of a universe that grew ever increasingly hostile around him, eventually culminating in the eruption of the Last Great Time War between the Time Lords and the Dalek Empire. Despite his efforts to stay out of the war, the Doctor was forced to participate from time to time - either due to Time Lord manipulation or outside intervention. Eventually, the Doctor succumbed to despair after failing to save a single life due to the Time Lords becoming more war-like, and chose to regenerate into a warrior incarnation in the hopes of ending the war once and for all.