The Daleks created a void ship, which weakened the barrier between parallel universes. Torchwood further weakened the barrier by starting "ghost shifts," which brought the cybermen over. For clarification, watch "Army of Ghosts" and "Doomsday".
- I thought the Cybermen were sealed inside their factories? I know they spent a while crossing the Void; how did they even leave Earth's orbit? If so, how did Torchwood manage to get them and no other humans from the parallel universe to cross over? Sniping is AwesomeDefeat the Sniper 11:06, April 12, 2015 (UTC)