[quote=Our established population counts]

Human pop: 9000
Uri pop: 4300 (300 in Zerabil's realm)
Mer pop: 7000
Cimex pop: 8000
Outsider pop: 90
[/quote]

When you first look at it you'd think that the Ciemx would be outnumbered with their 8000 vs the 13,300 Uri and humans combined. But the 4000 Vestec-worshipers aren't fighting the Cimex, they're fighting the Confederates, so that's probably minus 4000 humans in addition to however many more get killed/have to fight on that front.

So now we're somewhere around 8000 Cimex vs 8500 humans and Uri, I reason.

But then you have to realize that Ialu (and probably msot of the others on the human side) isn't even going to bring half his total population. He doesn't have that many warriors. He can't support an army that big. He can't even afford to equip most of them with true weapons or armor, so half his army is just going to be skirmishers that throw stuff using the Wi. At most he could muster like 1/4 to 1/3 of his people, and that's huge. The Cimex, on the other hand, are all warriors from my understanding.

So with my reasoning the Cimex will have the advantage of terrain, defensive battles, their fortress-hives, and even numbers. There's also their crazy adaptation and hivemind shit that could prove to be a nightmare.

Of course if Ialu succeeds in conquering the Garakain Kingdom and brings their chaos dragons and stuff, this might go down better, but frankly Ialu is an idiot. His strategy is to just charge right into the jungle and burn down the trees to make way for his army. He might leave a huge trail of destruction, but in the end he'll most likely get defeated. And while this will be a nice distraction, in that time I doubt Zerabil will manage to destroy all the other hives. 

How would the humans even know where the Cimex hives are, anyways?