Hogwarts: the Duelist's apprentice

This is heavily based on a cosplay couple of OCs my wife and i made so I have to give partial credit to TheCloneDoctor for this one. This takes place after the main canon when Harry's Ron's and Draco's kids are all going to Hogwarts to give me a bit more story freedom. So my headcanon is in place about the things that might happen with that. Rated M for lemons and violins