Companion (Doctor Who) "Face the Raven", but in a subsequent episode ("Hell Bent") her time stream is frozen at the moment of death by the Time Lords so that they can interrogate her about the Hybrid; the Doctor takes advantage of this to save her life, but she remains technically neither alive nor dead, does not age or have a pulse. After her departure as a companion of the Twelfth Doctor, she teams with the immortal Ashildr and travels in a stolen TARDIS. Other companions died in alternate timelines or alternate lives. "Brigade Leader" Alistair Lethbridge-Stewart, "Section Leader" Liz Shaw, and "Platoon Leader"
Companion (Doctor Who) from the spin-offs when doing so, including Jack's colleagues Gwen Cooper and Ianto Jones, and Sarah Jane's 'family' Mr Smith, Luke Smith and K-9 Mark IV. Other former companions from both the classic era and revived series have also returned as guest stars in the spin-offs, including Martha Jones on "Torchwood", and Brigadier Lethbridge-Stewart and Jo Grant on "The Sarah Jane Adventures". K-9 Mark I has also been spun off into its own series, albeit with an independent continuity. When "Doctor Who" returned to television in 2005, the companion characters played a slightly different role, partly due to a strong