What is great about KoW is how versatile it all is, as clearly demonstrated by this thread.
Whatever army you feel like basing them on, if you are looking to add some mythological flavour, and create some elite troops, then I suggest looking into the creation myth of Thebes with Cadmus.
Basically they planted dragons teeth and from the ground sprouted warriors. Admittedly in the myth the warriors went ahead and basically killed each other on the spot… but your version doesn’t have to go like that.