Ninth Doctor (The Curse of Fatal Death)

In another universe, a Time Lord calling himself the Doctor  travelled with a companion named Emma in a TARDIS shaped like a police box in his ninth incarnation. After an encounter with his old enemies, the Daleks, and the Master, a fellow Time Lord with whom the Doctor shared many centuries of conflict, he regenerated four times in quick succession, ultimately transforming into a thirteenth and female body.

Biography
This "Ninth Doctor" 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 had 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. The Doctor was 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 nine hundred years. The Doctor warned the Master about the creatures' plans to exterminate him once his usefulness was at an end using smells in the language of Tersuran.

When the Doctor's attempt to communicate with the Master was discovered, he was shot by a Dalek energy beam. Emma was horrified until the Master confirmed the Doctor was in his ninth incarnation and would regenerate. Sure enough, the Doctor regenerated into his next incarnation. (TV: The Curse of Fatal Death)

Behind the scenes
In PROSE: The Tomorrow Windows, in a scene in which the Eighth Doctor is being shown his possible futures, he sees "a listless-looking man sat on a sofa beside a girl in a red dress in an unconvincing medieval dungeon". This is interpreted by some as a reference to The Curse of Fatal Death.

Similarly, in PROSE: The Gallifrey Chronicles, there is a passing reference to the Doctor having "three ninth incarnations", which some believe is a reference to the Ninth Doctor played by Christopher Eccleston, this Ninth Doctor played by Rowan Atkinson, and the Ninth Doctor from the Scream of the Shalka webcast played by Richard E Grant.

However, after a detailed examination of the larger contexts of the source texts of both Tomorrow and Chronicles, this wiki's community overwhelmingly decided that these references were not sufficient to refer to Fatal Death and Atkinson's Ninth Doctor. Thus, it is the policy of the wiki that there is no particular evidence that The Curse of Fatal Death does occur in the DWU.