Wow omg so many FEELINGS! I loved the hurt/comfort and the high level of emotion in this story which still remains very really and doesn't seem forced or overdone. I've seen certain variations of this backstory for Antonin and it's quite different from my own headcanon and I've never liked it overmuch but it fits very well with the rest of the story and Antonin's desire for revenge may be wrong but it is SO understandable. His romance with Flitwick was heartbreaking and beautiful - I never thought I'd like paring with Flitwick but well this kinda changed my mind lol.
I also love how they were driven apart by something other than the light/dark agenda and that it was FLITWICK who screwed that part of it up and that Antonin just couldn't bring himself to hurt his lover, which to me just screams "this boy could have been ok if he just hadn't been tossed out to feel like no one gave a fuck about him". The ending is wonderful too - how after everything the most important thing, overall, is still each other.