I feel let down by Butcher in this one. Peace Talks was barely a 2.5/5 entry in the series, and was itself a letdown after the phenomenal Skin Game (still in my top 3 Dresden Files, 6 years and a partial series reread later).

This book, and its predecessor, needed editing. He could have crafted one finely tuned explosion of a book instead of two disappointing, bloated whimpers. This book delivers on the promise of its title and its setup in the last book, and delivers 300+ pages of Battle Ground as every faction and surviving character from almost every book in the series comes together and clashes for the future of Chicago. Epic sets the ground floor and Butcher sprints off of that starting block and doesn't look back.

The problem is this is 300+ pages of DragonBall Z: a well written fight scene, the tensions escalate, another almost identical fight scene, an ally arrives, another fight scene, the two combatants power up and the fighting continues, we then move on to the next bad guy and have a fight scene... wash, rinse, and repeat for the entire book. It became monotonous in its uniformity even though I love me a good fight scene, and Butcher writes a good one. He wrote an entire book of them. So why didn't I love this book? First off, this was too much of a good thing. It's like if I ate a party sized bag of M&Ms. I love M&Ms, but I don't need a giant bag of them all at once.

Second and furthermore, spoiler territory.

Spoiler

Halfway through the book, Karrin Murphy is killed off. She doesn't get a glorious, epic scene where she saves the day. Instead she dies by a cop cliche, a bit character with poor trigger discipline and a jumpy attitude, away from the big epic fight that takes up 85% of this book. Her death is dwelt on for a few pages as Harry tries to get street justice on the cop. Then we get two pages at the end. And a few passing thoughts between the two points. This death and this eulogy did not do justice for the readers to a character who has been around since the first book. I have been expecting her death at some point, especially after her body was broken, but I was expecting it in the penultimate or final books, not here and now. And not like this. She has worked to change the police and law enforcement for the better. She has been a bridge between the ordinary people of Chicago, and the supernatural.
Removing her leaves a void that the greater story will be hard pressed to fill. And if we are going to ignore those angles going forward, Butcher is doing his world, his characters, and his readers a grave disservice. This character death, handled this way, at this point in the planned series, has me questioning if I want to see this series through to the end. This didn't gut me like her physical injuries did. Like Michael's physical injuries did. Like the losses that Harry suffers during Changes.

Third, the super important character and situation that was focused on for over half of the last book, Harry's brother Thomas and his out-of-character actions, are sidelined on Demonreach island and barely mentioned or thought of at all. It's like Butcher and Harry both just forgot about this heavyweight fighter who is near and dear to Harry and at least one faction of the accorded nations, who is just left out of this book.

Fourth, remember at the end of the last book when Blackstaff tried to kill Harry? Remember when the White Council was casting side-eye at Harry for every little thing he did? Butcher doesn't. Harry doesn't. Blackstaff doesn't. We just set all that aside to focus on the Big Bad of the book.
It's like old times, four or five books ago, because it is cool. Because it is convenient. Not because it makes sense. We return to this point in the last few pages where we establish that yes, these things are still problems and will be dealt with in later stories.

Fifth, If Harry can summon Demonreach to grab Titanita from the shore, why didn't he try to grab the new Big Bad when he was traveling to the island (closer, and on water where magic is usually weakened)? Was it that she was too powerful, that she cannot be grabbed by such a maneuver? That's not made explicit in the text. When he hops off the side of the boat and speaks to Demonreach, I thought that is what he was aiming for. Another reviewer had the same problem with that scene.

And last, this is maybe just an authorial voice, written who knows how long ago, echoing wrong here in 2020, but the flip flopping of the police force as keeping the peace and then itchy trigger fingers causing problems rang wrong to me. And then there was the fast commentary that the Fomor ran into problems on the South side... what are you implying here, Butcher? This is an escalation of your very, very white Chicago in ways that make me uncomfortable as an empathetic reader.

I will buy the next book when it comes out, but Butcher has lost the goodwill he had with me and is up to bat with two strikes, and will need to earn my time and money to finish this series out past book 18. I say this as a fan since around the 7th or 8th book, when a friend shoved a stack of paperbacks at me and said "READ. You will enjoy them." She was right. And for your reference, dear reader, she and I talked about this book yesterday when I finished it, and she is also on the outs with this series because of the poor handling of these two books.