Jul 17, 2021
This is a very classic use of a prologue, don't let anyone tell you it's out of fashion.
If you're looking for things to improve, I think you should establish the relationship type between Harkam and Sebastion. For all the reader knows, they're brothers, friends, master/servant, even mortal enemies forced together. Later on the relationship is stated as lord/vassal, but that really could be in like, the second paragraph. If the reader gets a sense for how they 'should' be talking to each other, it will seem more natural even without changing anything.
You might also consider giving the reader more direction on whether these are the good guys or the bad guys (the people you're supposed to root for or not) Given that I'm going back to this prologue after knowing the events, I can't tell whether he's a vampire hunter, or a vampire himself thirsty for some fairy blood a la True Blood, or what (disclaimer; I don't actually know they're vampires I'm not caught up with that detail yet)