"Yeah, I'm not sure anyone knows exactly what Fou is. Well, Merlin always calls him Cath Palug, but..."

Maybe Ritsuka should just stop trying to explain things she doesn't understand while she's ahead.

"Oh! The Director's not a teacher? I was at Chaldea for a job, basically." There's a long pause as she evaluates what to say without actually ruining the mood here. "I guess it still is, technically, but a lot's happened since then and I don't think that's the kinda story for right now..."