Quite honestly, every time one of my characters has come into RP contact with Salazar or the Immortal Hunter, I've been quite impressed, although in our encounter this morning, I would have enjoyed a little more insult slinging before the pew-pew commenced (although the fighting was fun, and the completely flukey kill at the end made me laugh)
Oh, and about the "how to make Salazar more scary" idea, I think that you're trying to overdo it slightly: Murdering children? To my way of thinking, it just seems pathetic. They can't even fight back and Salazar is killing them for the sake of it, as if he's too scared to face people who would have a fair chance against him. Fine, it makes him seem pure evil, but it does slightly diminish his scariness.