@Razion,
As much as i want to agree with you on Velen winning, my undieing love for Sylvannus makes me stubborn. Sure Velen is probwbly the greatest followe of the light, with the most knowledge of it, who says it gives him unspeakable power? As being a preist right down to his loving core, i don't think he has the ability to actaully harm others. He might be the greatest healer on the planet or he can be just a herald, a spokesperson of the light.
Even though Sylvannus is an undead, vulnerable to the affects of holy magic, she is powerful, even by Scourage records.(the little killed by Godfrey was to show that Sylvannus mortal, like us) Given the fact that she has spent years uiliminating thr Scarlet Crusade, she might now eveery tick in the book about Priests. She has thr ability to wicked poisons, and extreme aim, dark magics and even being of two forms. Her Banshee self has led her to you many abilities in bodily form. She even has a one shot K.O. Arrow which she can use, this is probably not true but i have been trying to read around this. If in a "fair" fight between them, i would not expect Velen to simple call down the Light to purge the land and instantly vaporise Sylvannus. Even if he did have th ability to use harmful spells, Sylvannus is a damn good ranger, if in woods or even open ground, i would hink she would still be able to dodge most spells(if they are not instant cast.) If Velen is a pure healer, say disc speced, his sheilds would be powerful, but not powerful enough to stop her magics, even if it is, we know not of what Velen can actaully woth his gifted powers.
Lets say Velen is the traditional preist who pops a sheild and casts a ultra smite, Sylvannus would probably be like a hunter, say MM specd with some shadowy spells, she can stil unload a lot of attacks by the time Velen is down casting, she even has an interupt that could probably bust some ears. With Velen staggers around, she can simply put that K.O. show in him and done!
...or Velen could simply block it and hit her with ultra smite, they both have a good chance of winning, without the enivroment or time of attacks, i would say possibly 50-50 chance of them winning if they stick with fighting one on one.
Please dont scream at me for saying the ubsurd, but this is just a theory.