Ninth Doctor (The Curse of Fatal Death)

The Ninth Doctor was a possible future incarnation of the Eighth Doctor.

Biography
When the eighth incarnation of the Doctor looked into the Tomorrow Windows, he saw this incarnation as a possible ninth incarnation, as well as another which would not be and the one which would. (EDA: The Tomorrow Windows)

This incarnation met the Master on the planet Tersurus, after the Master asked him to, and announced his retirement from universe saving. He wished to settle down in domestic bliss with his companion Emma. He confronted the Master's various traps- each Time Lord having travelled back in time to bribe the castle architect to plant various traps in the Master's case and negate the traps in the Doctor's-, before being captured by the Daleks, whom the Master had recruited as allies after a trap the Doctor had modified resulted in the Master being trapped in the sewers of Tersurus for over a thousand years (The Master falling into the sewers and spending three hundred and twelve years climbing out of them on three separate occasions). The Doctor warned the Master using smells, the language of Terseran, about the creatures' plans to exterminate him once his usefulness was at an end.

When the Doctor's attempt to communicate with the Master was discovered, he was shot by a Dalek energy beam and regenerated into his next incarnation. (DW: The Curse of Fatal Death)

Behind the scenes

 * Like The Curse of Fatal Death, this incarnation of the Doctor was not considered canon. However, EDA: The Tomorrow Windows later brought him into canon as a possible future incarnation.