Carnell was a psychostrategist who worked with Servalan. He successfully predicted Coser’s breakdown, and that his crash landing on a deserted planet was faked and that he was alive.
He later realised that Coser had taken a slave girl named Rashel with him, an element he had not predicted. Realising his plan would fail, he left Servalan’s base, leaving her a farewell message.
Trivia
Carnell also appears in the Doctor Who novel Corpse Marker, written by Chris Boucher, and Scott Fredericks reprised the role in the audio series Kaldor City.