Katherine was surrounded by the Vampire Elite group set up by Darain under the order of Ermanno. Ermanno set up Jerome, He made Jerome go to Katherine on the premise that Jerome, who's undercover as Elgart would only scout to prove the existence of the Chosen in the Riverbed City.
Ermanno didn't believe the hooded figure completely, so he plans to expose Elgart(Jerome) if the hooded guy is telling the truth, they will surely get the Chosen and expose Elgart(Jerome), But behind Ermanno's agenda, he wanted the hooded guy to be wrong, he was actually emotionally attached to Elgart(Jerome) he thinks of him as his little brother.