Until the Full Moon(1996)

Full Moon ni Sasayaite

After ten years apart, aristocratic vampires and childhood friends Marlo and David are back together- as fiances! Being half werewolf and half vampire, Marlo undergoes a peculiar transformation, becoming a woman rather than a beast under the full moon. So there's no problem for a wedding and David's womanizing fangs- right?

(Source: Kodansha USA)

Note: Includes the Kanzenban exclusive two-part extra story "Dragon to Majo (ドラゴンと魔女)"