Sono Vampir wa Tadashikunai Yume wo Miru

I don't quite get that they call me by tactless name, "vampir." She is all that I desire. Louis, a vampir boy lived with the Kamuro family as a "brother-in-law" in a home of human being. He had hoped it would last forever, however, peaceful and pleasant days with his beloved sister, Harumu, suddenly collapse with an appearance of another vampir, Noah. (Source: Shueisha, translated)