I'm leveling a (crafting) alt in EP and i'm doing the quest in Deshaan where you get the "Blessing of Saint Veloth" in order to defeat Vox.
The description of the buff reads:
"The Blessing of Saint Veloth sears Daedric and Undead flesh with holy fire"
Which got me thinking, that might be cool to have in PvP against vampire (undead) players.
So i went to Blackwater Blade and sure enough, the buff still shows up in the UI.
Now the question is, does it actually do any bonus damage to vampire enemy players?
