Just some questions I wan't to ask:
A: What are Mechanithralls powered by? Its not steam...I think. But what goop powers them? Why can't Cryx use that goop for everything else?
B: Are Iron liches powered by the same goop+Magic that powers mechanithralls, or are they powered by steam+Magic?
C: Where does Cryx get its goop? That stuff has to come from nature, chemicals need to be made from somewhere (Magic can't do everything. Magic is BASED off of magic goop. Eyes of a newt and stuff. You need newts for that). And I don't think the lands of Cryx have any natural growth left.
D: Where does it get its bonejack skulls from? Are those creatures extinct now?
E: Where does Cryx get smart people from? It would be suffering major brain Drain as only limited amounts of its population can be ingenuitive and capable of progress, and they can't just birth more like the living. Because after a while, Cryx would run out of immortals as they die, and aren't replaced that fast. And once the last immortal genius dies, so does cryxes progression. Unless they resort to stealing more ideas.