Ooo, this is chilling. You get a real sense of how powerful Fenrir feels, and everything in his experience confirms it. That's what makes it so frightening in my mind - not that he's doing these gruesome things, or even that he enjoys it, but that we see no one to stand against him.
This is dark fic at its darkest and most hopeless, the kind you're almost afraid to engage with because you don't want the darkness that close. Most excellent work!