The Laboratories of Life
The Eastern side of the former Grand Civilization was central to one form of magical study: The study of magical life and it's creation, and the modification of the mundane with magic. The Grand Laboratory of Life was the core of this practice, and from it's halls came the creation of magical warbeasts and superhuman soldiers alike. A creature's natural form became suggestion rather than law, and illness was a thing of so far in the past that nobody remembered. It seemed like with time and study, even the human form could be transcended with the grand magics worked in the laboratory. The sky was the limit (quite literally, for those given wings) and the civilization would reach for it.
And then came the fall.
Those in control of the Laboratories of Life did their best to maintain the knowledge, the magic, that had made the future seem so bright. But as centuries pass, scrolls and codexes fade and tear, the old enchanted apparatuses lose power, the magical creatures interbreed with their mundane cousins. The laboratories dramatically changed the makeup of the flora and fauna of the East, as it's products spread through the land, but that didn't increase the durability of the lab itself. But the true successors of the great empire have, against the odds, managed to maintain their grandest achievement to some level, and as we bring ourselves back to civilization our greatest scholars seek to reconstruct that which was lost. The laboratories will hum with the magic of life again, and our armies will break the enemy with control over life itself.
---
I'll work on a civilization proposal later. This is my idea for the tech, and I have others that I'll work on as well. The idea is that hopefully our side will start with some magically enhanced warbeasts or maybe even people.