"A lesser one, not even one of the great Old Ones, would be enough to devastate a city; we play under the shadow of forces so sinister that a momentary relaxation of vigilance would see all that is human blotted out."The Old Ones are creatures of colossal significance, outclassing every other entity humanity has encountered across all dimensions. They exist as godlike beings in their own universes, and seek domination in ours by whatever means necessary.
Their intrusion into our plane of existence would constitute a Case Nightmare Green, the worst possible scenario The Laundry can imagine. Two of them have been encountered, however indirectly, so far.
- ↑ p46, The Atrocity Archives, Orbit, 2011