Unbound Doctor

An incarnation of the Doctor in an alternate universe was exiled by the Time Lords of that dimension at the end of his second incarnation. His TARDIS materialised in Hong Kong on 30 June 1997, the eve of the Handover to Chinese rule.

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. (NOTDWU: Sympathy for the Devil)

He later travelled to Skaro where he helped Gillen and the other Thals to help stop the Daleks. He created at neutraliser which changed a Dalek to think that a Dalek was Davros. This created some dissidence among the Daleks. He suggested an allience between the Daleks and Thals so that they could stop the Quatch. (NOTDWU: Masters of War)

Appearance
This Doctor had grey, swept back, longish hair. He also mainly wore the attire of his previous incarnation.

Behind the scenes
A bit of a myth has arisen in fandom that David Warner appeared in AUDIO: The 100 Days of the Doctor, but neither he, nor this character, appear at all in the story, though the Sixth Doctor did mention an alternate Doctor that was described in a way that matches this character.