Unbound Doctor

An incarnation of the Doctor in an alternate universe was exiled by the Time Lords of that universe at the end of his second incarnation. Instead of being exiled to the 1970s, he was sent to the late 1990s. Because of this, the Doctor was not present to help UNIT as the Third Doctor had assisted them in the prime universe.

He could speak Mandarin, Cantonese, Manchu, Mongolian and Hokkien.

To the Chinese, he was known as Hu (the Tiger, for his courage), Hu (the Fox for his cunning) and Xue (Doctor, he who tends to the sick). The last of these was his personal favourite. (AUDIO: Sympathy for the Devil)

History
After being put on trial by the Time Lords, the Doctor was told that he would be exiled to Earth in the 1980s. However, he was instead sent to Hong Kong on 30 June 1997.

Immediately after leaving the TARDIS, the Doctor bumped into Marcus and Adam. He followed them to the Little England, a pub run by Aistair Gordon Lethbridge-Stewart. The Doctor recognised the Brigadier and convinced him that he was the same person who he fought Robot Yeti with in the London Underground.

During their conversation, a Chinese plane disguised with chameleon circuit technology flew over them and crashed onto a nearby mountain. The Doctor and the Brigadier went to the crash site and helped the pilot get out of the wreckage and recover. UNIT arrived and brought the pilot to a nearby monastery. At the monastery, the Doctor heard that Ling saw a man change his appearance and realised that the Master was on the crashed plane.

The Master revealed himself by releasing an alien parasite which had been kept trapped at the monastery. The Doctor talked with the Master and made a deal. The Master agreed to stop his plan in exchange for the Doctor's TARDIS. The Doctor tricked the Master by saying that the Little England was his TARDIS. The Master attempted to cross the Doctor and leave him trapped in Hong Kong with the parasite. Instead, the Doctor took the parasite into his TARDIS while the Master went into the pub. The Brigadier came with the Doctor and they dematerialised to Mongolia. The Doctor dropped the parasite into a test area seconds before it was hit by a nuclear bomb and it was killed.

Instead of returning to Hong Kong, the Doctor and Alistair decided to travel through time and space. (AUDIO: Sympathy for the Devil)

He later travelled to Skaro where he helped Gillen and the other Thals to stop the Daleks. He created a neutraliser which altered a Dalek's mind so that it would believe that it was the returned Davros. This created some dissidence among the Daleks. However, when the new threat of the Quatch attacked Skaro, the Doctor suggested an alliance between the Daleks and Thals so that they could stop the Quatch, he and Alistair acting as the alliance's military leaders so that the Quatch could not predict what their opponents would do. With the Quatch defeated after the returned Davros sacrificed himself to destroy the equipment keeping them in this reality, the Doctor departed, although Alistair remained to help mediate the new Dalek/Thal alliance. (AUDIO: Masters of War)

The War
At some point, a great war was waged which saw the Doctor fighting alongside the Master against some other enemy, with the natives of the planet Tramatz being a key player in one side of the conflict. (AUDIO: The Very Dark Thing, The Emporium at the End) Towards the end of the War, the Master had acquired a weapon that would destroy the enemy at the cost of essentially destroying the universe as well, with the Doctor fleeing the conflict in the hope that the Master would be unable to activate the weapon without him. (AUDIO: The Emporium at the End) After the war had ended, the Doctor adopted the title of "King of the Universe", much to the anger and displeasure to many races and people. (AUDIO: The Library in the Body)

Meeting Bernice Summerfield
With the war's aftermath causing the universe to face collapse, the Doctor travelled to the prime universe to find Professor Bernice Summerfield, hoping that he could latch onto her unique artron energy signature to anchor him to that universe. Instead, it dragged her back into his own. Returned to his dying universe, they visited to The Library to find knowledge. He wanted to protect the Library from the Kareem, until he realised the Library was a parasite. (AUDIO: The Library in the Body)

Despite the Doctor's protestations that Planet X was boring, Bernice managed to persuade him. He was arrested upon arrival for being too interesting. He discovered that the populace was decreasing due to the population being processed to be boring, believing that they would be protected from the wider universe if nobody was interested in them. He escaped and met Ego where he was invited to a suicide party and re-arrested. In the final confrontation with Prime Minister 470, he exposed the truth about her reign while she was trying to torture him, encouraging the rest of the population to explore possibilities rather than being boring all the time. (AUDIO: Planet X)

The two of them then visited Tramatz to stop an imminent attack but got distracted by the singing river. When Benny saw a unicorn he told her to talk to it to calm it down. It became glaringly obvious that a weapon that had ended the war was warping reality and making people unaware of their impending doom. After the weapon was disabled, he decided to visit Admiral Effenish in order to try and stop the war from restarting. (AUDIO: The Very Dark Thing)

The TARDIS then received a distress call from the end of the universe from the Mother Superior to take her to the Emporium. He met the Manager, the Master in disguise, and found him familiar. He was escorted out of the building for trying to sneak around the Master's offices. He later decided to sell his memories to help people escape this universe, only to learn that he had already sold them to keep this universe alive. With this revelation, and his subconscious recognition of the Master, the Doctor realised that the Master's portal, which was allegedly sending lucky people to an alternate universe, was actually disintegrating them and creating the illusion of accelerated universal destruction so that the Master could guarantee his own escape. The Master was subsequently thrown into the portal and disintegrated, leaving the Doctor and Benny to explore this universe and find another way to save it. (AUDIO: The Emporium at the End)

Other universes
In another universe, the Doctor didn't run away from the Master's attack of Hong Kong and he grew to like his exile. The Sixth Doctor and Evelyn Smythe accidentally travelled sideways in time and helped the Doctor stop "an annoying man" from infecting the United Nations with Krynoid pods. The exiled Doctor helped repair the Sixth Doctor's TARDIS by donating his TARDIS' dimensional control. (AUDIO: The 100 Days of the Doctor)

Appearance
This Doctor had grey, swept back, longish hair.

Initially he wore the attire of his previous incarnation. (AUDIO: Sympathy for the Devil)

By the time of his journey to Skaro he had taken to wearing a ruffled shirt, dark suit and cape. (AUDIO: Masters of War)

Behind the scenes
At one point, a myth arose in fandom that David Warner appeared in AUDIO: The 100 Days of the Doctor. In actuality, neither he nor "his Doctor" appear at all in the story, although the Sixth Doctor does refer to a character resembling this one.

Y Doctor (Sympathy for the Devil)