The real reason why Marius Von Raum and Nastya Rasputina never met is because Nastya treats her violin like Gunpowder Tim treats his weapons - that is to say, she's never without it and she cares for it greatly. On the other hand, Marius has and will continue to throw his violin at people if he thinks it's funny, and has lost too many to count.
Edits because I was a fool:
It's a viola IT'S A GODDAMN VIOLA. Nastya plays viola and I somehow thought she played violin.
They did meet in canon. They did also perform together. I did not know this when I made this post.
Thank you to the people in the notes correcting me here......... It's so funny and also painful to me that people keep finding this incredibly wrong post and liking it anyway.
Particularly embarrassing given that I PLAY VIOLIN and NASTYA IS MY FAVOURITE CHARACTER.
Everyone go home post cancelled I guess-