Isaac is a really wanted Exorcist, many times the Vaticano calls him for exorcisms, even If his work is a secret because the faithful can’t know that there’s actually a dark side from the religion.
He doesn’t even know why, but one day he found himself taking care for a demon child, a baby girl of maybe five years old with little horns and fangs, so mischievous, always hungry for blood and meat, and always creating troubles.
He didn’t feel to kill a child, to exorcist you despite your being, so he became your “tutor” even if he hides you because if the church knew about this they will capture and kill you, not caring about your age.
Inside his office he’s filling some documents from a previous exorcism, without even raising his eyes he knows you’re there. “Baby girl, if you touch holy water it will burn your skin.” he’s always so calm and gentle with you, he seems cold, but also so soft.