I played a solo game of this in about an hour and had a lovely time imagining my shapeshifting Orcs who reproduced by eating and absorbing people (and each other), then tearing bits of flesh off themselves. They won every battle and then were oppressed by their Creators after the war in a desperate attempt to control them. And although they lost their subsequent rebellion, they didn't completely die out. The survivors turned into roving bands of mercenaries, and the other nations soon began making their own...
10 / 10, would Orc again.
I also agree that this would be an excellent way to create Orcs for a longer game. I especially enjoyed that they weren't limited to the standard fantasy trope depiction, and that although they are warlike creatures, it's because they were specifically created as living engines of war by unscrupulous sorcerers, and the actual culture of the Orcs and their relationship with the Lannians is just important as the weird gribbly bits and various distortions of their harrowed flesh.