Kiston

Kiston was a mechanical engineer in Lytton's mercenary company. He was summoned to make repairs and adjustments to Davros' life-support chair after his ninety year imprisonment. Davros took control of Kiston's mind, and used him as an agent in his plans to take control of the Daleks. He was killed by Daleks loyal to the Supreme Dalek. (TV: Resurrection of the Daleks)