What does a cape do? It covers up your shoulders and back, yep.
It gives you a cool collar that a vampire would wear, yep.
But what does it do more than any of those other things? It makes you look totally, incredibly awesome!
Every decent vampire needs a cape. Since you probably can't turn into a bat or do any of those other vampire tricks, we think you should wear this cape so everyone will be so taken with what you're wearing they won't ask you to do any transformations.
Looking good, Vlad!