Hakuouki Shinsengumi Kitan (Light Novel)

Disguised as a man, Chizuru Yukimura has come to Kyoto searching for her missing father, a doctor who developed a magical elixir that increases the drinker's speed, strength and healing abilities. Instead of her father, however, she stumbles across a battle between the Shinsengumi and the Furies, evil vampire-like creatures of their own making.