i was wandering with the Dawnguard Rune Axe, the enchanment says it deals sun dmg based on the number of undead i killed, so does that mean i can kill 1000 undead and it will do 1000 sun dmg or is there a limit to the amount of undead i can kill like 50 or something

I would like to know that too, but is there a way to get one on the vamp's side?

well seeing how its meant to kill undead i dont think vamps will be able to