- It is not known for how long the Watcher had been observing the Doctor.
The Watcher, apparently on his own accord, transported Nyssa from Traken, a planet which would soon die in the entropy wave, to Logopolis and safety. Later, apparently working on the Doctor's instructions, he piloted the TARDIS from Logopolis to keep Adric, Nyssa and Tegan safe. It was during this voyage that the Watcher engaged Adric in a private conversation.
A different version of the Watcher, called the War Watcher(or sometimes simply "Warrior") told the Eighth Doctor to drink the potion that would make his next incarnation a Warrior.(Which he did in "The Night of the Doctor") This version of the Watcher is implied to exist in between the eighth and War Doctors, like how the original Watcher existed in between the Fourth and Fifth Doctors.
The Twelfth Doctor saw the Watcher before his death. Later, when he did regenerate, the Watcher attempted to help the regeneration pass, but the Valyard froze the Watcher and the Doctor in time so that he could posess the Doctors' body. However, the time energy extended the Doctors' regeneration cycle, creating a second Watcher, a "Time Watcher" since he was made from time energy. .
The Time Watcher merged with the Thirteenth Doctor as he regenerated into the Fourteenth Doctor. .
Habits and Quirks
The "War Watcher" was similar to his normal counterpart, but had a black body with white eyes. He also had a more visable mouth and a red sash, similar to the War Doctors' sash.
The "Time Watcher" was identical to the normal Watcher, but with a blue and black color scheme.
Behind the scenes
- In the novelisation of Logopolis, the fact that the Watcher was the Doctor was indirectly alluded to during the TARDIS scenes where Nyssa and Adric were being taken away from Logopolis by the Watcher, allegedly at the Doctor's request. While the Watcher was never heard to speak on-screen, the novelisation suggests that Adric and Nyssa could hear him, possibly by telepathy. Both of them find the voice familiar, but are unsure why they recognise it.
- The nature of the Watcher's conversations with the Doctor and Adric was never revealed. Logopolis suggests that the Doctor was made aware of his impending regeneration due to his statement "It's the end, but the moment has been prepared for." The knowledge passed to Adric is never revealed, although after the transformation, Adric does show an unexpected knowledge of regeneration in Castrovalva.
- The Watcher of the Doctor's old friend Rallon appeared in Divided Loyalties, merging with the Celestial Toymaker – who had possessed Rallon's body for his own – after Rallon's death to keep the Toymaker in check in future, the transition from Rallon to his Watcher causing the Toymaker's personality to change as though he himself had regenerated. This Watcher was known as the Observer.