Alex Campbell (Restoration of the Daleks)

Alex Campbell was a companion of the Eighth Doctor.

An alternative version of the Doctor's great-grandson, Alex was taken from his universe by the Dalek Time Strategist and joined the Doctor in his adventures, travelling with him and Cass Fermazzi.

Early life
Whilst Alex was mostly human, he was also part-Time Lord due to him being the Doctor's great-grandson. (AUDIO: Meanwhile, Elsewhere)

The Dalek Time Strategist found and captured Alex during his sojourns through the multiverse and attempted to use him to manipulate the Eighth Doctor into ensuring the destruction of Gallifrey and end the Last Great Time War. The Doctor refused and revived him from a cryogenic casket after thwarting the Strategist. (AUDIO: Restoration of the Daleks)

Travels in the TARDIS
Alex joined the Doctor in the TARDIS, but the Doctor kept him unaware that the version of him from his universe was dead, (AUDIO: Meanwhile, Elsewhere) having been killed by the Daleks. (AUDIO: To the Death)

Upon arriving on Shimmer, Alex and the Doctor met a future Alex and Cass Fermazzi, who confirmed the Doctor's belief that there was a hyperstatic temporal incursion. Alex and the Doctor travelled from Shimmer to three other planets to close the resulting portals, with Alex meeting Cass for the first time from her perspective whilst on Hervandel. Upon arriving on the EC-141, he destroyed the ship's engine before going back in time with Cass and meeting his past self on Shimmer; once the situation was resolved, Cass joined Alex and the Doctor in the TARDIS. (AUDIO: Meanwhile, Elsewhere)

Alex, the Doctor and Cass travelled to Station Twilight and descended to examine the Vespertine, where they found Hudson Sage living inside a time lock. Alex and Cass used his memory recorder to look back in time and learnt that the Doctor had been on the ship with Bliss, a companion that the Doctor had no memory of. Following the Vespertine's destruction, Alex told the Doctor that he believed that the Doctor's timeline had been changed, but the Doctor theorised that the timelines of everybody outside of Hudson's time lock had been changed. (AUDIO: Vespertine)

Personality
Unlike his other self, Alex was enthusiastic about travelling in the TARDIS. He was flirtatious and had some knowledge of temporal mechanics. (AUDIO: Meanwhile, Elsewhere)