But that's the thing. If the Ascians really were the Warriors of Darkness, they wouldn't work against the Light. They'd instead cooperate with the light and ensure that the balance of light and darkness was kept. At least as far as Lahabrea was concerned, the Ascians (other than that one white-robed emissary) don't really seem all that interested in cooperation moreso than they are with reviving Zodiark to supplant Hydaelyn as the guardian force of the world, which is not at all what the Warriors of Darkness would do, unless they're just as ignorant as the Warriors of Light are.