Reapers

"There's been an accident in time. A wound in time. They're like bacteria, taking advantage"

First Regular Appearance

Father's Day

Before the Time War, any tangles in Time were moderated, controlled and fixed by the Time Lords. But in a universe without them, this process became more organic and terrifying. For the Reapers, voracious winged creatures who feed on the power of time, would be unleashed and they would only leave when there was nothing left to consume. When Rose crossed her own timeline to save her father, the Reapers arrived to sterilise the resulting wound in Time, and the thing that could save all those trapped in the paradox was the sacrifice of a hero.