Wow, what a fantastically original and moving story. I especially love their "meet cute" story, with its echos of Harry meeting Ron on the train, and of course Filius would know Russian and be dressed like a miniature Eustace Tilley. I love the backstory you've given Dolohov - the wizarding world is crueler than the Muggle one, I think - and the play on Filius' name. And the way the whole story is behind the scenes of canon until the very end. Oh, and it's beautifully written, too.