Damon knew he was to blame for the part in her abduction. First of all, he hadn't stayed by his Queen's side throughout her coronation night which brought the hunters to attack her. He then selfishly asked Cassius to save her by any means necessary, and that was by giving her the damned vampire's blood. She'd awakened her vampire side now because of him, and she was suffering because of him-
"If you continue wallowing in self-pity, I might just put an end to you myself," Gabriel said quietly, glaring at him before returning his attention to the castle. He continued to speak as he put his hands in his pockets; it was frustratingly similar to Cassius. "Stop blaming yourself. Both of you."
Damon glanced at Finn, who whipped his head to the side to look at the vampire. It seemed his thoughts weren't the only ones being read.