Going back to the EstHogg assassination, If you notice, he directly lecture's vidofnir AFTER the stabbing. This leads me to believe that the attack was purposefully nonfatal
otherwise he'd be lecturing a corpse which is infinitely more dumb.
So my conclusion is that Nidhogg's hatred is solely towards the Ishgardians and he bares sympathy/mercy towards his own dragonkind.
What he did was the equivalent of a violent spanking and warning that he'd do much worse if they even think of being  race traitor.
otherwise he'd be lecturing a corpse which is infinitely more dumb.
So my conclusion is that Nidhogg's hatred is solely towards the Ishgardians and he bares sympathy/mercy towards his own dragonkind.
What he did was the equivalent of a violent spanking and warning that he'd do much worse if they even think of being  race traitor.
