You weren't there. In the final days of the war. You never saw
what was born. But if the time lock's broken then everything is
coming through. Not just the Daleks, but the Star of
Degradations. The Horde of Travesties. The Nightmare Child. The
Could-Have-Been King with his army of Meanwhiles and Neverweres.
The war turned into hell! And that's what you've opened. Right
above the Earth. Hell is descending.
[ Dr. Who, The End of Time (Part Two) ]