Season 7 is all about fighting evil in all it's forms. Over the last few years she's faced all sorts of evil creatures,
but they've all had their own code of twisted ethics that make sense to them. However I wanted to create an enemy so
disturbing and different and malignant that didn't follow any sort of rules at all, they were to be utterly evil because their
existance was totally different to anything ever seen or heard of before.
The Home of the 13th Doctor