The Echo is the hidden blueprint of the universe present in the informational space of everything within that universe. With the right technology or miracle, it is possible to reconstitute an entire universe from a single living instance of that universe.
Echoes are present strongly in Refugees who will recall their universe clearly. Others who have not the same attachment will find that any Finalised universe begins to fade in their memory as if it never existed.
The longer a Refugee survives after the [[Lexicon#Finality#|Finality]] of their universe, the more they are subject to Drift. Drift is the effect where they begin to change to suit their new adopted universe. Entities that wish to reconstitute the old universe or who wish to consume the last morsels of a finalised universe will pursue Refugees before Drift takes hold.
The strength of the Echo may also power abilities for a Refugee which may not exist in this reality. These will ebb as their finalised universe is extinguished.