/lit/ - Literature

I need some help here.

I have a story a group of humans resistance fighting against vampire rulers, The protagonist is a reluctant member who was accidently turned into a vampire. Now he's forced to use his vampire privileges to spy on the count for resistance.

The problem is: why would the count let him into the castle? He has enemies of his own, other vampires, so he wouldn't just let anyone in, not even other vampires, without a reason to trust them. I'm struggling to come up with a reason.