you made a common mistake there maxos was 'not' the progenitor of the dragon knights, he was merely the most powerful of them ever to have come into being
Not quite. He was never a Dragon Knight, but a wizard so powerful and wize that dragons gave him the power to make others Dragon Knights. Before that, only dragons could make someone a Dragon Knight.
Talana was a Dragon Knight, and she was able to make the Dragon Slayer into a Dragon Knight.
Was that just because she was dying, or is it possible for the Slayer-turned-Knight to make new Dragon Knights (without sacrificing their own life)?