One of the nodes mentions that they have captive Dravanian (of which we're to slaughter).



I suppose this isn't too surprising since we know Midgardsomnr's children have existed since the 1st Astral Era, but this at least confirms that Dravania has been dragon territory at least during the Allagan Empire's reign.

Additionally, we know that the did not stop with just Mercydian dragons, but they captured and enslaved Dravanian dragons as well! So this bit of info might very well give credence to the theory that Nidhogg was the powerful dragon that escaped from Asyz Lla thousands of years ago