Are we not all tainted souls? Vampires, corrupted souls with unliving bodies, alive yet dead the bridge between the two. Werewolves souls 'tainted' with the blood of the wolf not fully man nor beast but the median between both. Neither of us in complete.
As their sister I'll stand with my shield siblings, face the world may non overtake us. Standing as the sword and shield between the tainted and mortal. Vampires shall not perish the sun by any means, nor will the Dawngaurd destroy us besides humans make poor vampire hunters, they are frail they're mortal and they're corruptable body mind and soul.
Word of Advice (and a favor): If you give up you die so continue to stand as a monument to your strength, show the world you aren't to be trifled with. Give your enemies a decent target.