Dalek Sec

Dalek Sec was a Supreme Dalek and was the leader of the Cult of Skaro. He was to come up with new ideas of survival and of exterminating the enemies of the Daleks. During the Last Great Time War, Sec and the Cult stole the Genesis Ark and used their Void Ship to hid in the void. After the Genesis Ark opened and the Doctor activated the Void, Sec did an emergency temporal shift. (DW: Army of Ghosts/ Doomsday)

Landing in New York 1930, Sec and rest of the Cult of Skaro starting experimenting on people, resulting in Pig slaves. Dalek Sec operated the Final Experiment on himself, making him a Human-Dalek hybrid. He slowly started to regain human emotions, and was betrayed by the rest of the cult because he was "corrupt". He was chained up, and eventually sacrificed himself for the Doctor. (DW: Daleks in Manhattan/ Evolution of the Daleks)