The Doctor (Battlefield)

This Doctor was one of the Eighth Doctor's many possible ninth incarnations. (EDA: The Tomorrow Windows)

Biography
The Doctor and his companion Anna travelled to Exeter in the 21st century where they encountered one of the Doctor's previous companions; Tegan who cursed the Doctor for what her time with him had done to her. Later in the TARDIS, Anna found a diary that Tegan kept during her travels in the TARDIS, the Diary warned the reader that the Doctor maniplulates his companions into killing for him. Anna realised that this had happened to her and asked the Doctor to take her home, which he reluctantly did. (ST: Good Companions)

After finding another companion, Guinevere Winchester, the Doctor then arrived on the Schrödinger Institute, a research station in deep space where sabotage of the station had caused a temporal echo to occur. The temporal echo meant that the Doctor and Guinevere could not be seen or even touch anything until someone else did so. The Doctor managed to rewire a control box after a technician had worked on it which broke the echo, allowing the Doctor and Guinevere to leave. (ST: Revenants)

Travelling alone, the Doctor went to visit his old friend Greenaway. The Doctor told Greenaway that his life support machine was unable to keep him alive any longer. In an act of mercy the Doctor turned off the machine and left in his TARDIS, unaware that Greenaway managed to survive. (ST: Greenaway)