Ummm hit the armor cap of 567 then it won't be much of a problem even on master? That is the best I can help you with this rather uninformative rant.
First of all, NPC arrows are, indeed, hella strong. For some reason they always seem to do waaaaay more damage than your arrows.
Second of all, yes, hit the armor cap. Acquire 567 armor and 85% magic resistance, and transcend mankind! Take arrows to the face with only a few points of health lost! Laugh in the face of Legendary Dragons as you shrug off their Ice Breath unharmed!