" Wait, I can’t kill him,” he said, as if remembering something. “Ian made me swear not to kill anyone tonight.”
“I release you from that vow!” Ian shouted.
“Oh, but I have a real problem,” Vlad said with merciless mockery. “In fact, it’s like a sickness for me, right?”
“I was wrong!” Ian yelled. “Not a sickness, it’s a bloody marvelous gift. Now, practice that gift before I’m nothing more than a silver-pronged husk! "
― Jeaniene Frost , Into the Fire (Night Prince, #4)