This Doctor is the one who survived through all the trouble he has caused over 60,000,00 years ago. He was nearly killed by P.D. (Past Doctor) and got sent into a dimension where dinosaurs were still alive. The dimension in question is a very dark, grey and gloomy one. But the master trapped them in the dimension and was then killed by P.D. with a sword.
This Doctor will appear in the new special episodes after "Army Of Metal", the only episode in season five.