Blood: The Last Vampire (2000)

Japan, 1966. Saya is part of a secret team destroying demons. She is sent undercover as a student at the Yokota Air Base in Fussa-shi, Tokyo, just before Halloween. She discovers that two of her classmates are vampires in disguise just as they are preparing to attack the school nurse; meanwhile, her colleagues have discovered another vampire acting as a bartender in the local red-light district. A spectacular battle ensues.