A/N: Time to meet Sebastian! Quick note that in this universe, Kurt and Blaine didn't know him in high school.
"Have you always been this insufferable?" Kurt challenges as he fills a mug of coffee in the break room. "I find it hard to believe you got this far in life with that personality."
Sebastian chuckles, takes a sip of his own coffee before he responds. "You know, not everyone thinks I'm insufferable. Some people actually quite like me."
"Who? Your parents?"
"That's original, Kurt," Sebastian says flatly.
"Well I'm pretty sure everyone here would agree with me."
"Maybe," Sebastian muses. "I guess you should be thanking me then."
Kurt snaps his head to the side to look at Sebastian. "Thanking you?"
"Yeah," the other man says easily, quirking his head to the side.
"Why would I thank you for being an intolerable pain in my ass every single day?"
"Well the alternative is special treatment, and I don't think you'd like that either."
"What?" he asks, eyes narrowed.
"You know, like how everyone else tiptoes around you ever since–"
"No," Kurt says, cutting him off firmly. "You do not get to talk about her."
"Calm down," Sebastian says, raising a hand defensively. "No special treatment, remember?"
"Fuck you," Kurt says, turning his back on the other man and making his way out of the room.