Cole Jarnish was a pilot and companion to the War Master.
Biography
Meeting the Master
Cole was piloting a ship coming down to Arcking, when the Daleks, in search of the Master, attacked the ship, killing most people on board apart from him and a small number of others. He was placed in medical care, where he met the Master, pretending to be Doctor Kellar.
When the Master asked for a pilot so he could use a landship to search for an energy source, which was rumoured to be why Arcking had such mysterious properties, he requested Cole as a pilot, alongside Phila as a companion, albeit briefly. Upon finding the source, they found that it was sentient. After leaving it, due to it talking to them and refusing to go, their landship was attacked by Daleks, and they were forced to leave it. Phila was killed, and Cole left Arcking with the Master in his TARDIS. (AUDIO: The Good Master)
Companion to the Master
Cole asked to land on a planet, which was in need of saving, so he could be its saviour. The Master left him at a village, so he could go grow grapes, and Cole was put to work by the villagers. He discovered that the villagers were dying, due to fallout of the Time War, so he created a suit which would keep them alive. He managed to get all of the villagers into a suit, but the suits turned them into robotic like creatures, only in need of revenge. They chased him out of the village and he escaped to the Master, after which, they left the planet. (AUDIO: The Sky Man)
The Master took Cole to No. 24 Marigold Lane, Stamford Bridge in the 1970s where a Time Lord was keeping the Heavenly Paradigm under lock and key. After finding this Time Lord, the Master gleefully killed Cole to power the Paradigm, his usefulness having come to an end. When Cole, as his last act, protested against this callous treatment, the Master coldly reminded him that he previously had agree to make "any" sacrifice in exchange for his help. (AUDIO: The Heavenly Paradigm)