I can't say about Skyrim, but from what little I've read Dragons don't seem anymore destructive in general than any other race on Nirn.
They do however seem to be of Mer like jinxed proportions, to the point that cursed to fail comes to mind.
So hopefully some scale to degrees of hostility may be possible.
I'd like if the civil war of the Nords emerged to occur at the same time as a civil war between Dragonkind.
Those were red dragons, these are black. They could be different, but defiantly food for thought.
In Akavir the reds were tamed as well by the Snakes, the blacks fled but then due to further conflicts all types were said to be destroyed.
In Skyrim the Cliffracers drove them to Cyrodiil and made them disapear.
So the Dragons could be remnants from either of these groups, or unique ones all together.