A banger of a book!!!! It’s hard to find anything about this book that I didn’t love. I loved the story start to finish. The horror elements in it were done so well (even if that might be due to my own fears of caves and claustrophobia). The humor and banter intertwined in the story were the perfect touches to keep things from feeling too serious without losing the plot. It was also strangely wholesome, which I didn’t expect, and I would be lying if I said I didn’t tear up towards the end. Start to finish I consumed this like it was my last meal and would happily cease to exist knowing this was the last thing I read.

( Rounded up to a 5 )
4.5⭐/ 5⭐

What Stalks the Deep delivered an eerily atmospheric horror novella that while being humorous & wholesome in a way. While not as creepy as the prior novellas it is still entertaining and engaging. Though not quite a spoiler, initially my thoughts when I heard what the setting was to be a coal mine I was hoping that the supernatural/cryptid would be a booger. They are a creature of folk legend in the Appalachian region. I was genuinely surprised when that was not the case.

For a novella it packs slow-burn creeping tension and immersion that led me to finishing the 192 pages in one sitting.

The Sworn Soldier series continues to be one of my absolute favorites, I will read as many of these novellas as Kingfisher wants to write. That said, I think the first two installments were a bit stronger than this one. That said I did read an eARC (Thank you, Tor!), so I look forward to reading it again in its printing.

This installment sees Easton visiting America (and I really hope we get another novella set in America!) and the commentary regarding Easton's perceptions and experiences is hilarious. I also liked the setting of mining town Appalachia, which lends itself well to the tone of the series.

The first half feels stronger than the second, but that may also be a false impression I have that isn't fair to the story, as this one takes a slight departure from the courses of the first two. However, I did love the characters we met in this book and learning more about Denton who we met from the first in the series. This book also felt a bit cozier than the first 2, more horror-lite, which I didn't mind as it felt fresh for the series.

That all said, if you love creatures and the ideas Kingfisher comes up with to explore them, you'll love this. You also can't go wrong spending more time with our favorite sarcastic, charming soldier!

While not quite as creepy as the preceding two Sworn Soldier novellas, What Stalks the Deep was still engrossing and entertaining. I am immensely enjoying this series, and I feel like I need a full-length novel soon. Maybe something that leans into the horror genre hard, or gives us more back story on Alex and their history.

Alex Easton has every reason to refuse the trip to America, and if it had been anyone other than Denton, it would have been refused. Knowing the horrors they'd already faced together, and that Denton needed help, Alex and Angus sail into Boston harbor. Denton's cousin has gone missing in an abandoned mine rumored to be haunted. What they find is more than they could have anticipated.

The Sworn Soldier series has been amazing, and this is my favorite so far! Alex's humor was on point, Angus as gruff as always, and all the characters in this book are so fleshed out and real. T.Kingfisher does such an amazing job of making this mine so dark, and so creepy, and so claustrophobic that I felt a bit out of breath while I was reading it. (No, I did NOT let out a breath I didn't know I was holding!) And of all the things I thought they'd find in the mine, I could never have anticipated what was there.

Always a pleasure to read anything by T.Kingfisher. Thank you to NetGalley and the publishers for the advanced reader's copy in exchange for an honest review.

Another beautifully haunting entry into the Sworn Solider series, as expected. We join Easton and Angus on a journey to America, pulled there by a desperate Denton who needs someone with the same supernatural experience. Someone who will not only believe him, but is capable of handling whatever they find at the end.

What they find, or ultimately finds them, is a primordial terror unlike anything the group could imagine. Death surrounds this new phenomenon, and it takes all the courage any of them can manage to push through to this new ending.

All in all, another five star read from Kingfisher. Here's hoping this series continues for a very long time, bc Easton and Angus are probably two of my favorite people in literature, and I foresee their adventures going many places.

A fantastic addition to the series! While not a stand-alone, it can be read without reading the previous novella in the series. Hits all the high points of Kingfisher's horror writing -- there were points where I set down my copy & shrieked, before immediately picking up & reading at breakneck speed. Highly recommend!

This is the 3rd book in the Sworn Soldier series and as soon as I got access, you bet I was reading it. This is like reading about old friends who constantly stumble into bizarre, slightly terrifying situations and somehow make it weirdly heartwarming. We have a creepy old mine shaft that turns into deep cave exploring (something I’ve always been fascinated by) and of course, not everything is what it seems. I love these books.

T. Kingfisher delivers another eerie, atmospheric triumph with What Stalks the Deep—a gothic horror steeped in the haunting ruins of Appalachian coal country. Alex Easton, the reluctant hero with a soldier’s grit and a skeptic’s edge, is drawn into the heart of a decaying West Virginia mine, where shadows stretch long and the past refuses to stay buried.

Kingfisher masterfully blends creeping dread with sharp character insight, crafting a world where the supernatural feels both menacing and tragically human. The mine itself is a character—claustrophobic, echoing, and hungry. As Easton unravels the mystery behind Dr. Denton’s missing cousin, the story morphs into a harrowing rescue that’s as much about surviving the horrors within as it is about confronting one’s own ghosts.

With unnerving imagery, dry wit, and an aching sense of loss running beneath the horror, this novel is a slow-burn descent into madness and memory. Kingfisher proves once again that true terror often lies in the places we once trusted—and the things we thought we left behind. A chilling, beautifully written tale that lingers like coal dust in the lungs.

I want like 20 more Sworn Soldier books. We've gotten three in about four years and as long as Kingfisher is putting them out, I'm reading them.

Easton and Angus are, as always, delightful. Easton has a unique voice while keeping with Kingfisher's usual humor. I love that Kingfisher will pull in characters from the first book. It really gives that historical mystery feel where mysteries will often feel like they start with a friend or friend of a friend having an issue. This makes the world still feel familiar while traveling to new locations.

I love the queer representation as always. Easton is non-binary (the country Easton is from has pronouns for some specific people/things, and soldiers use ka/kan) and there are also other queer characters that I was happy to see.

The three novellas so far have also all felt pretty different from each other in what the mystery/horror is, which I feel is hard to do when you only have so much space.

Another easy five star read from T. Kingfisher

While this book is a thrilling conclusion to the trilogy of Sworn Soldier novellas, any one of them can stand on its own as a suspenseful story. This final book takes us into the mountains and deep caves of West Virginia. Every chapter, as the plot grew and expanded, I found myself kicking my feet and punching the air with excitement, and then as it went on I forgot that I had a body because I got so wrapped up into the unfurling mystery. T. Kingfisher is a master of storytelling and horror, and I cannot recommend these books highly enough - or just this one, if you want. But read it.

The sworn soldier series has become like a spooky warm blanket for me. I love these books so much and the newest is no exception. The characters and relationships in these books are so perfect, and it truly is like visiting old friends. Old friends that manage to get themselves into really weird positions, that is.

The other thing that I love so much about these books is how much I learn from them. This and the first book especially, are almost great introductions to biology and science for readers. It really is fascinating to learn so much and be so entertained in such a short book!

In short, I will read every book in this series as long as T. Kingfisher wants to write them.

First, thank you to NetGalley and the publisher for this ARC in exchange for an honest review.

No one is more surprised than I am to be giving this 5 stars, something I rarely do. I'll be honest, I read the first 2 books and wasn't a huge fan. I gave them both 3 stars. I do like other Kingfisher stuff, though she can be hit and miss for me. When I saw this pop up on NetGalley, I put in for it on a whim, since I often don't get approved for Tor stuff, and honestly assumed I'd be declined. When I got approved, I had just finished a book, so I started reading it right away.

This book immediately drew me into the story in a way the other books hadn't. Alex's humor seemed sharper and more frequent here, which I loved, and was one of my favorite parts of the series as a whole. Also, the core conflict - a person has gone missing in a mine - was immediately introduced, another positive shift from the other stories. Additionally, Alex, now a veteran of not only the army, but also two separate supernatural threats, is no longer spending the first half of the story trying to convince themselves that the issue can't possibly be supernatural, a trait that really annoyed me in book 2. Furthermore, Kingfisher does an excellent job of making the mine just the most genuinely creepy place to be. I don't consider myself claustrophobic, but her descriptions of what roaming around in that mine was like had me squirming. Finally, the story didn't go the way I expected. Without spoiling anything, Kingfisher throws a nice curveball in there in terms of what the danger actually is.

If you like horror fantasy with some humor thrown in, I highly recommend this. It's a quick, creepy, atmospheric read.

After reading the first two books in the series, I expected What Stalks the Deep to be far more bone-chilling, and it was definitely unsettling but somehow managed to also be wholesome at the same time. The setting of a coal mine in Appalachia was an excellent choice and was very convincing as a place where scary things happen and things lurk in the dark. T. Kingfisher also has a knack for introducing new body horror just when you least expect it, and she definitely followed through with that. If she writes more Sworn Soldier, I'm excited to read it!

4.5☆ rounded up to 5

OH BOY did I enjoy this one! There was a sense of dread and horror that I have never experienced in a book, but after the first reveal, I never regained that feeling (hence docking .5)


But this installment in the Sworn Soldier series was absolutely solid. The narrators inner voice was as delightfully humorous as always, juxtaposed with the dark story and content it was a perfect combination.

In hindsight, this is probably my second favourite in the series thus far, beating out What Moves the Dead by a narrow margin.

Hoping beyond hope we get a 4th novella!

#indigoemployee

I started reading this book based solely on the fact that it’s by T. Kingfisher, but I was pleasantly surprised to learn it takes place in an abandoned coal mine! What a cool setting. I love abandoned places and underground caves, so this was right up my alley.

Our intrepid hero Alex Easton is back again on a new adventure, this time in West Virginia. An adventurer has gone missing in a mine and Alex must help to find him.

I loved the eerie atmosphere that was set up at the beginning and the way the setting feels all encompassing. Definitely the strongest part of the book. I also loved all the characters and their relationships. Genuinely loved the whole book.

I also loved how, in what felt like exactly something T. Kingfisher would do, this story starts out as horror and ends as something wholesome. No spoilers. But it was really nice. I enjoyed it.

Overall, this was a strong entry into the Sworn Soldier series, and it might even be my favorite book in the series. I have no idea if there are going to be more Sworn Soldier books or not—the ending certainly alludes to that possibility—but I won’t be mad if there are because I really enjoy these novellas. I will read anything T. Kingfisher writes.

I love the sworn solider series, and this is a solid addition to it! I wasn't the biggest fan of the installment before this one, but What Stalks the Deep adds back in some of the elements that I fell in love with in the first book. It was fast paced and full of that mycological horror that Kingfisher is so good at.

Thank you to Tor Publishing Group and NetGalley for the eARC!

This was phenomenal, and I read it all in one sitting. This was the first Sworn Soldier book that really truly scared me. The others were certainly eerie and spooky, but this one had me completely tense with the mystery of it all. I was blown away by the twists and I found myself endeared to the new and returning characters like never before. I didn't much care for Dr. Denton in the first novella, but I really like him in this one. This was twisty and mysterious and spooky and so much fun! Still has the trademark humor of the Sworn Soldier series but was absolutely gripping! The best one so far!

**A Dark and Atmospheric Delve into Mystery and the Unknown** What Stalks the Deep by T. Kingfisher is a gripping and atmospheric tale that masterfully blends suspense with a touch of the supernatural. Alex Easton, a cautious and reluctant hero, is dragged into a dangerous rescue mission into the haunted depths of a West Virginia coal mine that has earned a reputation for lurking terrors—and for good reason. Kingfisher’s storytelling shines in this chilling adventure, building a mounting sense of dread with each chapter. The eerie descriptions of the abandoned mine and the shadows that seem to dance just out of sight kept me hooked, and Alex’s quiet resilience adds a layer of emotional depth to the story. As secrets from the past and the mine’s dark history surface, the line between myth and reality becomes increasingly blurred. While What Stalks the Deep is less about outright horror and more about creeping atmosphere and slow-building tension, it delivers a truly immersive experience. The pacing is steady, and Kingfisher keeps the surprises coming—some unsettling, others thought-provoking. It’s a story about facing fears, both supernatural and personal, and doing what’s right when things seem most hopeless. Overall, a well-crafted, suspenseful read that provides plenty of atmospheric chills and keeps you guessing until the very end. Four stars for a story that haunts just enough to leave you looking over your shoulder in the best way.

What Stalks the Deep is the third novella following sworn soldier Alex Easton, and with each adventure I am more and more invested in poor Alex's misadventures. Alex is a soldier, and one who has been understandably traumatized by their wartime experiences. Of course in Alex's case there is also a significant amount of trauma related to more recent brushes with the weird and horrifying.

As this installment begins Alex's presence has been requested in West Virginia by previous ally Denton, to help assess a mysterious disappearance in an old coal mine. Alex and Denton are joined by Alex's aid Angus, and by Denton's close friend Ingold, an amateur scientist. What they find in the mines is better left discovered by the reader.

A significant part of the horror in this particular story comes from the reality of a coal mine and the natural potential for danger within. The descriptions of the feel of the stone pressing in all around in tight passages should be more then enough to discomfort readers even before stranger things begin to occur. Denton and Ingold also add a good dynamic to the story, with Ingold enjoying the possibility of new scientific discoveries and Denton falling more on the side of "burn it all down immediately."

I've very much enjoyed this series so far, and look forward to future Alex misadventures.