I have a theory on what are the corrupted eggs in the dreaming city. So the dreaming city had plenty of Ahamkara visitors plus one permanent resident. Now my theory is that Riven laid these eggs because dragon are reptiles. Although Ahamkaras can shape-shift people normally portray them as dragons/reptilian creatures. Now when Riven laid these eggs she scattered them all around the dreaming city. But then when the Taken traveled to the dreaming city, they corrupted the eggs similar to how they taint or blight stuff. Also the reason some these eggs are in the ascendant plane is that The Dreaming City is partly in the ascendant plane which could explain why it is in there or the Taken just took it with them for no reason.
perhaps this was part of the wish, that mara would get a throne world but it would be an ahamkara spawning ground