Tsukuyomi: Moon Phase

Tsukuyomi: Moon Phase (月詠, Tsukuyomi) is a Seinen manga series by Keitarō Arima. It first appeared as a serial in the monthly manga magazine Comic Gum from March, 2000 to March 27, 2008. The series spanned sixteen manga volumes that were published by Wani Books in Japan. The manga series was later adapted into a 25 episode anime television series by Shaft, and aired on TV Tokyo from October 4, 2004 to March 28, 2005. An additional OVA episode dubbed "Episode 26" was later released only on DVD on February 22, 2006

Plot
The story is about the relationship between freelance photographer Kouhei Morioka and Hazuki, a young girl who descends from a royal vampire lineage. At the beginning of the story, Kouhei travels to a castle in Germany to take photographs of paranormal phenomena for his friend Hiromi, who is the editor of an occult magazine. At the castle, Kouhei meets Hazuki, who feeds on Kouhei's blood and claims him as her unwilling servant. Although this "blood pact" is supposed to bind Kouhei to Hazuki as her obedient slave, her act has no effect on Kouhei. Following an action-packed sorcerers' battle in which Kouhei and his cousin manage to free Hazuki from her captivity in the dreary castle, Hazuki travels to Tokyo, and takes up residence with Kouhei in his grandfather's house in Japan. Hazuki claims that, because she fed on his blood, Kouhei is now her servant, but Kouhei continually refuses to obey her, especially when he thinks her requests are unreasonable. Despite their fighting, the relationship between the duo progresses over time — even in the face of repeated attacks by opposing vampires — until Kouhei becomes determined to protect Hazuki from the vampire servants of her family, who are determined to retrieve her by whatever means necessary.