This is great! Chilling and evocative, and two believable, three-dimensional versions of both John Dawlish and Alecto Carrow. Beautifully written, too. Your style both brings Dawlish close to the reader and reflects the effects of the curse -- great.
I'm impressed how believably you flesh out Dawlish: his confidence that he can have anything and, because of that, his fascination with what nobody else wants, his cruel streak, his stance on Muggles (of course there would not only be Death Eaters and "the good ones", but also those in between, those who have basic sympathy with their ideas but think they go too far of disapprove of their means). Everything about this man sounds absolutely right, plausible and in keeping with what little we get about him from the books.
Whatever the victory, he will emerge on the losing side. Either he was an enemy from the start who has been put to use, or he is a traitor who has fallen so weakly to the enemy’s control. -- He would.