Vampire Knight Vol 1

Vampire Knight by Matsuri Hino. A Shojo manga rated Older Teen, published in English by Viz Media.

At Cross Academy, the Day Class and the elite Night Class never mix, because the Night Class students are secretly vampires. Yuki Cross, the headmaster's adopted daughter, helps guard the secret alongside her brooding friend Zero, while harboring feelings for Kaname, the vampire who saved her life.