Regarding the voidsent being hungry for aether, remember what we learned about the sin eaters? they are hungry for living aether

Living aether so to speak has a balance of astral and umbral aether. With the sin eaters overaspected with one kind, they have the primal urge to go after the opposite either to rebalance themselves or convert it to their own

So with the voidsent, the same would be true, just the opposite kind of aether. Which means the bulk of the thirteenth is a dark reflection of the empty.


Which makes the power of Eden and Omega extremely disconcerting- Eden can outright manipulate any element and may have been the true reason the flood started. We still don't know what it was about Eden that made it register on Ryne's vision and the theory Urianger had about it being the first sin eater is questionable given its some sort of living machine.
Omega plausibly had the same power as Eden as it could create life even if the beings lacked a soul but tthe Ascians never did much with it besides having allag study it.