All the Windwracked Stars by Elizabeth Bear is a bit genre-busting. It is heavily grounded in Norse mythology with liberal sprinklings of sci-fi, steampunk and high fantasy.
After Ragnarok, of which there are and will be many, one Valkyrie survives because she ran away. Her name is Muire. When she comes back after the battle, wracked with shame, she finds a single valraven still alive who takes her for his rider. She heals him and, in doing so, turns him from a flesh and blood creature to one of metal and fire. Then she rejects him. Centuries later, Muire is living in the sole remaining city of Valdyrgard which is kept alive through technomancy while the rest of the world dies around it.
Mingan, the Grey Wolf (Fenrir?), returns to Valdyrgard, hunting for something. Muire senses him and believes she must kill him to avoid another Ragnarok. In tracking him down, she discovers that the souls of the Valkyrie have been reborn as new people. These new people don't remember themselves but Muire and Mingan know who they are. An ancient love-triangle is reignited. Muire wants to restore the Valkyrie to themselves.
I loved this. It is dark and sexy, full of flawed characters trying to do the right thing, but finding it hard to work out what that is. The characters are complex and complicated and so are the relationships between them. The villains have excellent motives and it is hard not to sympathise. The heroes want to do what's right, but the consequences of that are often wrong. They all struggle with the way they feel and the burdens they carry.
The language is lyrical and poetic. The rhythm is slightly odd but perfectly pitched. I really enjoyed reading it for the sake of the arrangement of the words. It was lovely.
If I have a criticism, it's that it is a shame that the only person of colour in the book is the most abused, damaged, infantilised and sexualised character in the book. Those two things didn't have to belong to the same person and it plays into some unpleasant racial tropes.
Other than that, this was one of the most engaging books I've read this year. I enjoyed it enormously and will definitely pick up more of Elizabeth Bear's work. Highly recommended!