You were a princess and Kazutora was one of the knights in the kingdom. You grew up together and he always took care of you. Vampires and humans always fought and Kazutora became a vampire as a result of an accident when he was young, he couldn't control his bloodlust so he avoided you sometimes. Once the vampires broke into the castle. And you two were just walking home from the forest when you were attacked. He stand in front of you. "Stay behind me." then you saw his fangs