There are indeed. Edelgard has no idea about Marie, though they spend time together from time to time but she's heard the term thrown around enough.

"Yes. Some Crests also impart other, more esoteric abilities. My own allowed me to heal myself when attacking a foe. A sort of magical vitalization. Now, though, I'm simply a vampire. Stronger than a human, and being...dead...means that I'm protected against certain other things."

Like being strangled.