The immortal and villainous John is Polus regenerated into human form. He is the leader of the Fades, and returns to Earth to rescue his wife, Natalie, from the torture of the Angelics.
About Joe Dempsie
BBC Americans will recognize Joe Dempsie from his days on "Skins," where he played fun-loving party animal Chris in the first two seasons. Whovians, too, will know him from the 2008 "Doctor Who" episode, "The Doctor's Daughter," which saw him in the role of a soldier named Cline. His additional credits include "Merlin," "This Is England '86," and "Game of Thrones."