Rebecca Yarros is taking Empyrean fans back to Basgiath War College sooner than expected.
While readers are still anxiously waiting to discover what happens after the explosive ending of Onyx Storm, Yarros’ next Empyrean release will not be Book Four. Instead, the bestselling author is expanding the world of Fourth Wing with Threshing Day, a new collection of thirteen stories centered on riders, dragons, and the day that changed their lives forever.
And with the September 29, 2026 release date now less than a month away, we finally know a little more about what the collection will contain.
Most importantly, Xaden Riorson’s Threshing story is officially included.
Yarros’ official Threshing Day website describes the book as thirteen stories from across the Empyrean world, including Xaden’s, making this considerably more interesting than a typical companion collection.
For readers who have spent the months since Onyx Storm theorizing about Xaden, Violet, the dragons, venin, and what could possibly happen in Book Four, Threshing Day gives us another reason to return to Basgiath while Yarros works on the next main novel.
Here is everything we know about Threshing Day.
What Is Threshing Day by Rebecca Yarros?
Threshing Day is a collection of thirteen stories set in the Empyrean universe, with each story revolving around Threshing and the bond between a rider and dragon.
It is important to make one thing clear:
Threshing Day is not Empyrean Book Four.
Yarros and the book’s official website have explicitly described it as a companion collection rather than the continuation of Violet and Xaden’s story following Onyx Storm.
That distinction matters considering how desperately fans want answers after the third novel.
Instead of moving the timeline forward, Threshing Day appears designed to move sideways through the story we already know, showing important moments that Violet could never have witnessed herself.
And that may be exactly what makes the concept so exciting.
The Empyrean novels are filled with characters whose histories with their dragons have mostly existed outside Violet’s point of view. Threshing Day finally gives Yarros the opportunity to tell some of those stories directly.
When Does Threshing Day Come Out?
Threshing Day will be released on September 29, 2026.
Rebecca Yarros’ official website lists the September 29 publication date, and the book is currently available for preorder ahead of its release.
That means Empyrean fans do not have much longer to wait.
The collection was officially revealed during the 2026 Conscription Day celebration after it had previously appeared for preorder as a mysterious untitled Empyrean project that specifically noted it was “not Book Four.”
That mystery immediately generated attention, and now we know exactly what Yarros had planned.
Xaden’s Threshing Story Is Confirmed
This is easily the most interesting new detail about the book.
Xaden Riorson will be one of the characters featured in Threshing Day.
The official website confirms that the collection includes Xaden’s story, meaning readers should finally get to experience the day Xaden bonded with Sgaeyl.
That alone makes Threshing Day feel much more important to the larger Empyrean series.
Xaden remains one of the most mysterious major characters in the books. Violet—and therefore the reader—has learned much more about him since Fourth Wing, but large portions of his past remain outside the main narrative.
His relationship with Sgaeyl is especially interesting.
We have watched the two interact throughout the series, but seeing the beginning of that relationship could reveal a completely different side of both characters.
And after everything that happened in Onyx Storm, any additional insight into Xaden is going to be dissected by fans looking for possible clues about his future.
Which Other Characters Are in Threshing Day?
For now, Rebecca Yarros is keeping most of the lineup secret.
The official description promises stories featuring fan-favorite characters and their dragons, but Xaden is currently the major character specifically confirmed by the official Threshing Day website.
That means earlier speculation about characters such as Rhiannon, Ridoc, Sawyer, Garrick, Bodhi, Imogen, and others should still be treated as exactly that—speculation.
Personally, I think keeping the lineup secret makes the collection more fun.
Part of the appeal will be opening each story without necessarily knowing whose Threshing we are about to experience. There are dozens of possibilities, and some of the most interesting choices may not be the obvious ones.
There is also one character fans would almost certainly love to see again: Liam Mairi.
Whether Yarros has chosen him remains unknown, but a Liam Threshing story would undoubtedly be one of the collection’s most emotional possibilities.
Why Threshing Is Perfect for an Empyrean Short-Story Collection
Threshing is one of the best concepts Yarros could have chosen for a book like this.
For every rider, it represents a defining moment.
Cadets enter the Threshing grounds hoping that a dragon will choose them. Some succeed. Some fail. Others don’t survive.
Readers experienced Violet’s extraordinary Threshing in Fourth Wing, where her decisions ultimately resulted in her bonding with both Tairn and Andarna.
But Violet experienced only one version of the event.
Every dragon has a different personality. Every rider enters the field with a different history. And every bond begins for a different reason.
By returning to that same event thirteen times, Yarros can tell thirteen completely different stories without making the concept feel disconnected from the main series.
One story could be funny. Another could be terrifying. Another could completely change the way we understand a character we have known for three books.
That flexibility is what makes Threshing Day such a strong idea for a companion volume.
The Deluxe Edition Includes 16 Full-Color Illustrations
There is another reason collectors may want the first edition.
According to Rebecca Yarros’ official website, the deluxe first edition of Threshing Day includes sixteen original full-color illustrations by artist Joe Requeza. The special edition is being offered in the United States and Canada while supplies last.
That feels particularly suited to this collection.
Dragons are obviously one of the biggest attractions of the Empyrean series, and illustrated scenes could give readers another look at characters and dragons they have previously only imagined.
Apple Books currently lists the digital edition at 224 pages, suggesting this should be a substantial companion collection rather than a handful of extremely short bonus scenes.
Why Threshing Day Could Matter for Book Four
The big question is whether Threshing Day will actually contain information readers need before Empyrean Book Four.
We don’t know.
Yarros has not announced that the collection is required reading before the next novel, and because it is specifically being presented as a companion collection, readers shouldn’t assume they have to read it to understand Book Four.
But I would be surprised if there weren’t details worth remembering.
One of the pleasures of the Empyrean series is how small pieces of information become more meaningful later. Dragon history, family relationships, conversations, political alliances, and details about Basgiath can all suddenly matter hundreds of pages after they are introduced.
Thirteen stories about existing characters and their dragons give Yarros plenty of opportunities to add to that mythology.
Xaden’s story feels especially significant.
His relationship with Sgaeyl, his family history, and everything that has happened to him during the series make his Threshing potentially much more than a nostalgic trip into his past.
I fully expect fans to be hunting for Book Four clues as soon as Threshing Day is released.
What Is Happening With Empyrean Book Four?
The good news is that Threshing Day has not replaced the fourth Empyrean novel.
Rebecca Yarros is working on Book Four, and she has previously made it clear that the companion project did not change her plans for the next main installment. When revealing Threshing Day, Yarros described it as a trip back to Basgiath for readers while she works on Book Four.
There is still no official release date for Empyrean Book Four as of September 1, 2026.
That is the most important thing for readers to remember when they encounter rumored dates online.
Until Yarros or her publisher announces a publication date, anything else is speculation.
You can follow our latest updates on the fourth Empyrean book here.
Yarros taking additional time with Book Four may ultimately be a good thing. Onyx Storm dramatically increased the number of mysteries the series needs to resolve, and with the Empyrean saga planned as a larger story, the next installment has a lot of narrative weight to carry.
Should You Read Threshing Day Before Book Four?
For existing Empyrean fans, I think the answer is going to be yes.
Not because Yarros has said it is mandatory, but because the concept offers exactly the sort of background information that makes a fantasy world feel richer.
If you care about the dragons, supporting characters, Basgiath, and the history behind the riders we have followed through three novels, this seems made for you.
And Xaden’s inclusion makes it much harder to dismiss Threshing Day as optional bonus material.
That said, this probably isn’t where newcomers should begin.
If you have never read the series, start with:
Reading the main novels first will give the characters, dragons, and events in the collection the context they need.
Threshing Day Is More Interesting Than I Initially Expected
When Yarros first revealed that her surprise Empyrean project wasn’t Book Four, I could understand readers feeling a little disappointed.
After Onyx Storm, everyone wants to know what happens next.
But the more we learn about Threshing Day, the more I like the idea.
Thirteen Threshing stories allow Yarros to revisit some of the series’ most popular characters without artificially extending Violet’s current storyline. We get more dragons, more Basgiath, more world-building, and potentially major pieces of character history that simply couldn’t fit naturally into the main novels.
And knowing that Xaden’s Threshing is included immediately raises the stakes.
I don’t expect Threshing Day to answer the biggest questions left by Onyx Storm. It isn’t supposed to.
What it can do is make us understand the characters—and particularly their relationships with their dragons—a little better before the main story continues.
Final Thoughts
Rebecca Yarros may not be giving readers Empyrean Book Four in September, but Threshing Day is shaping up to be much more than something designed to fill the gap between novels.
The collection arrives September 29, 2026 with thirteen stories built around Threshing, including the now-confirmed story of Xaden and his path to bonding with Sgaeyl. The deluxe first edition also features sixteen original full-color illustrations, making it one of the biggest Empyrean releases outside the main novels so far.
The smartest thing Yarros could do with a companion book is show readers parts of this world Violet never got to see, and that appears to be exactly what Threshing Day is doing.
Now the question isn’t whether fans will read it.
It’s how many Book Four theories thirteen new stories are going to create.
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