The Preachers

The parallel universe that spawned the Cybus Cybermen in was also home to members of a secret organisation dedicated to fighting and defeating the Cyberman, known as The Preachers.

The Preachers emblem, a circled "P", can be seen in places outside the parallel universe. It can be seen as faded graffiti on rusty bins outside Bernie's flat in Cardiff (TW: Ghost Machine), inside the present day Ritz (TW: Captain Jack Harkness (Torchwood story))

History
The Preachers were led by Rose's father, Pete Tyler, who was still alive in the parrallel universe, who was also joined by Jake Simmonds, Mrs. Moore and Mickey Smith, the latter from our universe. (DW: Rise of the Cybermen, The Age of Steel)

The Preachers were able to cross into our universe when Torchwood began to draw power from the Void Ship and hoped to use this as an advantage in defeating the Cybermen who had escaped their home universe. (DW: Army of Ghosts) They returned following the defeat of the Daleks and Cybermen, taking Rose with them, trapped in the alternate existance when she fell through the Void opened by the Doctor, leaving the Cybermen trapped in the Void. (DW: Army of Ghosts / Doomsday)


 * Presumably the Preachers are no longer an organisation, as the Cyberman had been trapped in the Void so there were no longer any to defeat.