Summary from Vampire Knights:

Since youth, Shin had a special ability to foresee dangerous situations. When his sister, Nao, was kidnapped by the people from a research center, Shin finally realized that he was not actually human, but a ‘virtual beast’ created in a genetic experiment. To solve the complicated mysteries revolving about himself and save his sister, Shin and his good friend, Tatsuki, embark on a perilous journey.