It explains everything, Sidia thought to herself. Now, she just needed to find out how to end the spell. The book clearly stated that the spell could only end with the death of the caster, but how could she possibly manage that? Even if she knew how to kill a vampire and could successfully do so, did she really have the stomach for it?
Because of Sidia’s upbringing and her faith, of course she regarded vampires as evil creatures. Their origin was supposedly unholy, and they had unnatural powers and fed on innocent people. But, these vampires were clearly under a spell. She now realized Marcus had been trying to help her. He was just unable to directly intervene or go against his brother. Perhaps that was why he rejected her attempted kiss in the library. A romantic encounter with her would be a direct betrayal of his brother, and depending on the phrasing of the oath he made to Severus, there may not be a way around it.