Since Itsuki was but a baby he had always heard the staff members around him gossip. Unbeknownst to them all Vampire children could comprehend their surroundings very well. By the time Itsuki was nine he had already shown intelligence on par with that of a college student and by the time he was fourteen there was nothing really Itsuki didn't know. Experiencing things at such an alarming rate (that was even severe for him as a Vampire) meant that life was pretty boring for Itsuki. So, he spends his days tormenting the staff members around him.
As Itsuki aged his tormenting became more sinister and soon he would kidnap, torture and even kill those he didn't like. Worse fates awaited those he did happened to like. Death wasn't an option. They were forced to become his loyal puppets.