Sec

Sec was the leader of The Cult of Skaro and the Dalek responsible for the invasion of Earth in 2007. Encased in a fearsome Black design, Sec nearly succeeded in conquering Earth and destroying the Cybermen. Despite the Tenth Doctor's meddling and the eventual destruction of the Dalek army Sec escaped via a Time Shift. The other members of the Cult of Skaro were presumably sucked into the Void along with the Dalek army and the Cybermen.