The Unclean

This amazing anime feature blends digital computer animation with the more traditional drawn animation cells. The moody artwork complements the story of Saya, the last true vampire. Saya must find and destroy evil blood-sucking creatures that are hiding, and killing, within a U.S. compound in Japan during the Vietnam War. They are called Chiroptera, and can take human form. The Chiroptera, are hematophagous bat-like creatures and are extremely long-lived with humans level intelligence. And Saya hunts them down using a katana, slicing deep into to the creatures to bleed them out before they can heal.
Based on the Manga, Blood: the Last Vampire by Benkyo Tamaoki.
Directed by Hiroyuki Kitakubo
Writen by Kenji Kamiyama