[He can sense the worry and the shock. But to be honest, he has expected a much worse reaction.]

Believe me, it would be better if it was like that.

[He decides to give the headmaster more information.]

I can sustain myself on animal blood and normal food, but only for so long. Sooner or later, I need human blood.

I need it in order to stay sane and in control of myself. I won't die without it, but as I said, I become very dangerous.