Vampire Stories: Brothers(2011)

"Vampire Stories: Brothers" tells a story about Sei, who finds out that he is a pure blood vampire from his older brother, Ai, and that he will turn at the age of 20. Sei has to choose to live or die, but what complicates his decision is his younger step sister, Midori, whom he cares for. What will Sei choose? To live or to die?