Hmm.. well, I don't know the name of the series you're looking for, but maybe I can give some recommendations...?
-Vampire Knight (you probably already know about this one)
-Vampire Game (I don't know if you know about this one or not; has some gender-bender in it...)
-Oresama Teacher (not a lot of gender-bender, but there is a little. Not supernatural, but the main characters get into fights often)
-Ouran High School Host Club (you might know of this one too; it's gender-bender but shoujo)
-Rosario + Vampire (don't know if you've read this or not; it's kind of ecchi, but there is action in it... but if you like action, then I would read this one instead of watching the anime, since the best fight wasn't even in it)
-Noblesse (you might have already read this one)
I know my recommendations aren't that great _ _'|| Good luck~