Amare Et Sapere Vix Deo Conceditur

About a woman vampire that is part an elite group, sent to destroy unfit vampires. She's on a mission to destroy an ancient vampire, a king. Set to go to his ball (where he collects more human women to seduce then kill), seduce him, then kill him before he actually notices what she's there to do, and runs away. The two connect on a different level, though some people may not see that. In the end, she kills the king, knowing she'll see him in Hell, again.