Anyone know what you have to do? The description says "Use the Special Power of Auriel's Bow". I used it in the battle against Harkon but I did more damage with my magic so.
I just did it, saved before and used Clear Skies. I was by Whiterun when I did it and had no idea the Sun would strike down those innocent Kahjiit merchants!
what is the difference between bloodcursed and sun-hallowed arrows?
Bloodcursed arrows shot at the sun will block it out. Shooting Sunhallowed arrows will make the sun shoot at nearby enemies (or pretty much anything living around you) and also explode if you shoot it directly at enemies