The art is gorgeous, and the backstory for Filch is brilliant. Your Filch reads like exactly the man into whom his story would have turned him, and his reaction seems very plausible. Interesting then to see how that contrasts with Albus's view from his ivory tower. His "you just did your duty", and also his reaction to the end, suggest to me that he tries to empathise (in his own, special way) but really has no clue what goes on in the trenches devised by the great men who pursue the even greater good. Great foreshadowing of the later Albus Dumbledore. Still, I can see where the attraction lies.