Blood, the Last Vampire
Everybody knows what a Vampire story is. It's about a seductive, mysterious, handsome aristocrat dressed in black with supernatural powers and a taste for attractive young women. Or it's about a seductive, angst-filled, handsome rich guy dressed in black with supernatural powers whose taste for attractive young people may be a bit more ambiguous. It takes place in the modern day or the fog-shrouded end of the Victorian era. Vampire hunters are a mix of rugged young athletic types who often fall for the vampire's would-be victim and eccentric grizzled founts of arcane knowledge who are acting without official sanction.
Then there's Blood, the Last Vampire. It's set on and near an American military base in Japan during the Vietnam War. These vampires are stealthy predators who work together. They don't seem to be undead; they might not even be supernatural, though just what they are is mysterious. None are wealthy or sophisticated, nor do they dress in black. Victims and intended victims are not chosen based on age, appearance, or romantic possibilities and they don't fall for the vampire hunters. The vampire hunters are clearly sanctioned by someone, though they're operating secretly. The old experienced vampire hunter looks younger than the rest of her team and does most of the actual fighting of the creatures instead of puttering around with musty old tomes.
So it's a Vampire story, but it's not a typical one at all. I found those changes refreshing, but it's a big enough departure that many people would not enjoy it, especially if they were looking for a romantic or erotic element. A lot of questions are left unanswered about both hunters and vampires and the story isn't all that long. The animation is well done, but has a darker, harder feel than the art style of most anime as well.
I recommend this anime, but a lot of people would probably dislike it for the same things I like about it. Because of that, I'm not giving a numerical rating.