As someone who hasn't read any Lovecraft since high school (and absolutely will not), I wondered how much of the mythos of Lovecraftian horror was contained. Upon further research, this story (and the one it is based on) are not part of the full Cthulhu canon, so the mentions are rather minor and the story stands on its own. 

This book does play a lot on identity and transformation by power and circumstance. As it is a novella, the story is concise, but unfortunately this means that many meaningful scenes happen off-page and are discussed by the characters. I like this one a lot, and would have loved an expanded version where we get to see those happenings. 

I think something that is a slight draw back for me is the MC acceptance of the racist assumption that he is a monster. He is thought to be one, so he loses his humanity and turns into one. But it felt close to equalizing the violence of an oppressive system to the reactions to that system. I think that the author's note adds a lot of context, and as someone that does not read author's notes often, I read this one twice.