They were competitors in a lot of ways based on the ruins of this place it almost seems like Ellethia was ahead of Taravast.

[ Considering the bits and pieces of information she had gathered about Ellethia and Taravast before the former's fall she shook her head. ]

Did Ellethia form an army to try and strike the undead first, and forced their able-bodied citizens to sign up? It would explain why the undead saw fit to destroy this place completely.