In Adastra, Interea, and Khemia there is mention of The Other, is this the entity present in Echo?
Um, sort of?
Whats in Echo has a lot of the same characteristics, but I'm not sure if its the same thing.
In Adrastea or Khemia (I forgot which) It is mentioned that the Other leaves patches of itself behind when it moves through an area. So the Echo abnormality could be a patch of the Other, but I'm not sure that was intentional by the writers.