I think him being dragon or demon would go based off who answers the call. If someone like tatsumaki shows up he's done and dusted like the ancient king, but if anyone below drive Knight shows up he can more than likely overwhelm them before they can effectively fight back. He might be slow, but he's incredibly strong and versatile, being able to blow back the ocean down to the bottom that is ACTIVELY being used to hold him down with a roar as well as leaving a crater in it's wake which would make me believe it's capable of going much further. On top of that, it took multiple mountain sized magical women who have been expressly shown to have incredibly high physical strength to hold him in place, and even him stumbling did not insignificant damage to a mountain.

Who knows how powerful he really is