.........You know, it super belatedly occurs to me that Sebastian would try to sleep with her if he thought that'd be the way to get information out of her. Canon approach and all. Y/N/hissss she'd rather drive a stake through his heart?
Mostly I'm imagining Athos' face if/when it comes up that "oh yeah... that guy bought me a drink when we first met and then we slept together during the AU. idk his name".