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Basgiath War College · Riders Quadrant

Threshing Day Book

Threshing Day is a companion anthology of thirteen stories, one for each of thirteen riders, and every story covers that rider's own Threshing. It is The Empyrean #3.5, published on September 29, 2026, and it is not Book 4.

Ancient pines and large claw prints in wet mud at dusk.
Thirteen stories, and they all start on ground that something larger has already walked.

The collection

Full title
Threshing Day (Wing and Claw Collection)
Author
Rebecca Yarros
Publisher
Red Tower Books, with Piatkus for the UK and Commonwealth
Published
September 29, 2026 (US first printing)
Length
224 pages
ISBN-13
978-1682818084
Form
Thirteen short stories, one per rider, arranged by year
Catalogue position
The Empyrean #3.5, a companion anthology
Point of view
Rider POV only. There are no dragon POVs
Attested chapter title
Trial by Fire, the opening frame
Official tagline
Thirteen unforgettable stories. One legendary day.

What the collection is

Every story shows one rider Threshing: the day the first-years of the Riders Quadrant walk into the valley and find out whether a dragon bonds with them, ignores them, or kills them. In the main series that day is told once, from Violet Sorrengail point of view. Here it is told thirteen times, by thirteen riders who were in the same valley on the same October 1.

The stories are arranged by year, and framed as testimony collected later. Two Basgiath dragonkind professors, Valin Kaori and Ellery Mynna, are credited with the opening chapter, and the collection presents itself as testimony transcribed from Navarrian.

All thirteen are rider POV. Rebecca Yarros has said the dragons know too much to narrate, so the dragons speak through their bonds and stay out of the narrator seat.

What the collection is not

It is not Book 4. The fourth main novel continues the story that Onyx Storm left open, and Yarros announced this collection specifically as not book four. Reading it will not advance that plot.

It is also not a novella. Thirteen separate stories, each with its own rider and its own year, is a collection rather than one short narrative, and the retailers list it at 224 pages.

What it does carry is the thing a companion collection is for: time with the thirteen riders at the moment their lives turned. The deluxe first edition adds sixteen full-colour interior pieces by Joe Requeza, colour endpapers and sprayed edges.

When to read it

Read it after Onyx Storm. The stories look backwards to events that happened years earlier, but several of them only mean what they mean once you have the main novels behind you. One story pays off a death that Fourth Wing spends its whole length preparing.

There is one small shortcut. Xaden Riorson's story was also posted free on the author's own site, so readers who want a sample before committing to the collection have an official route to one of the thirteen.

If you are still deciding where the collection sits, the reading order lays out the four books and what each one changes.

The thirteen, and their gates

Full story nodes appear below at their own spoiler level. Dragons are held out of this roster on purpose: for several of these riders the pairing is the reveal.
RiderRole in the quadrantStory gate
Brennan SorrengailLieutenant Colonel and mender. Eldest Sorrengail sibling and a ranking figure in the Aretian wing.Fourth Wing
Mira SorrengailFirst Lieutenant. Older sister to Violet, younger sister to Brennan.Fourth Wing
Xaden RiorsonWingleader, Fourth Wing. Son of the executed Duke Fen Riorson and leader of the marked ones.Fourth Wing
Garrick TavisSection Leader, Fourth Wing. Marked one and Xaden's closest friend.Fourth Wing
Dain AetosSquad leader in Fourth Wing, later Wingleader. Son of Colonel Aetos.Fourth Wing
Bodhi DurranSection Leader, Fourth Wing. Xaden cousin and one of the marked ones.Fourth Wing
Imogen CarduloRider in Fourth Wing, Flame Section. Marked one and one of Xaden's best fighters.Iron Flame
Rhiannon MatthiasCadet and later squad leader, Second Squad, Flame Section, Fourth Wing.Fourth Wing
Sawyer HenrickCadet from Luceras, later Executive Officer of Iron Squad.Fourth Wing
Ridoc GamlynCadet in the Riders Quadrant and one of Violet's closest friends.Fourth Wing
Liam MairiCadet in the Riders Quadrant. Marked one, Xaden's foster brother and Violet's bodyguard.Fourth Wing
Sloane MairiCadet in the Riders Quadrant. Liam's younger sister.Iron Flame
Aaric GraycastleCadet in the Riders Quadrant, entering under an alias. Third son of King Tauri.Iron Flame

Spoilers: Fourth Wing

This section contains material from later in the series.

Story nodes, gated at Fourth Wing

Established Brennan Sorrengail Dragon: Marbh. Role during Threshing: Not yet established in the novels. His own Threshing is one of the thirteen stories in Threshing Day (2026). One of the thirteen Threshing Day viewpoints. In the novels he is the brother Violet believes dead, and his survival is the closing reveal of Fourth Wing. His dossier is the only place in the collection where a Sorrengail sibling rides before Violet does, and his later role as a mender makes him the clearest example of what a Threshing bond turns into over a career.
Established Mira Sorrengail Dragon: Teine. Role during Threshing: Not yet established in the novels. Her own Threshing is one of the thirteen stories in Threshing Day (2026), and it is where her bond with Teine is covered. One of the thirteen Threshing Day viewpoints. In the novels she is the sister who tries to keep Violet out of the Riders Quadrant and fails. Mira is a serving officer by the time Violet reaches the quadrant, so her record is the one that connects the ritual to the career that follows it.
Established Xaden Riorson Dragon: Sgaeyl. Role during Threshing: Bonded Sgaeyl at his own Threshing, two years before Violet enters the quadrant. Sgaeyl had gone fifty years without a rider and broke the tradition against bonding the descendants of former riders to take him. One of the thirteen Threshing Day viewpoints. His story was also posted free on Rebecca Yarros's own site, so it is the one chapter of the collection that is publicly readable outside the book. He is the only viewpoint who already carries the responsibility for other cadets, so his Threshing is the one that shows the day from inside a command structure rather than from inside a first-year fear.
Established Garrick Tavis Dragon: Chradh. Role during Threshing: Bonded Chradh, a brown scorpiontail, at his Threshing. Chradh had previously bonded a rider from Garrick's own bloodline, which is part of why the pairing carries more than one signet. One of the thirteen Threshing Day viewpoints. He is the marked one Xaden trusts with the work that cannot be written down. His record is the bluntest of the thirteen on what the quadrant does to a cadet who has already lost his family to it.
Established Dain Aetos Dragon: Cath. Role during Threshing: Bonded Cath at his own Threshing, a year before Violet entered the quadrant, and was a second-year squad leader by the time she arrived. One of the thirteen Threshing Day viewpoints. He is Violet's childhood friend, and his loyalty to the Codex is the pressure that defines his first two years. Dain is the rule-follower of the thirteen, which makes his account the one that shows what the Codex asks of a rider on the day the Codex cannot help him.
Established Bodhi Durran Dragon: Cuir. Role during Threshing: Bonded Cuir at his own Threshing. The pair fight together from the Battle of Resson onward as part of the rebellion. One of the thirteen Threshing Day viewpoints. He is family to Xaden in the way that matters most in the quadrant, which is to say he is the one who stays. Bodhi carries the Riorson name without carrying the command, so his account is the one that shows what loyalty costs a rider who is not the leader.
Established Rhiannon Matthias Dragon: Feirge. Role during Threshing: Bonded Feirge at Threshing and manifested object summoning through the bond. Rhiannon rises from cadet to squad leader within a year. One of the thirteen Threshing Day viewpoints. She is Violet's closest friend in the quadrant and the first person to treat her as a rider rather than a liability. Her account is the one that shows the ordinary version of the day: a capable cadet with no dynasty behind her, hoping a dragon picks her.
Established Sawyer Henrick Dragon: Sliseag. Role during Threshing: Failed to bond at his first Threshing, repeated the entire first year, and bonded Sliseag on the second attempt. He is the canonical proof that a cadet who is not chosen can come back and try again. One of the thirteen Threshing Day viewpoints. He is the underdog of the thirteen and the only one whose first Threshing failed. He is the one rider in the collection who has stood in the valley twice. Nobody else can describe what the second walk in feels like.
Established Ridoc Gamlyn Dragon: Aotrom. Role during Threshing: Bonded Aotrom, a brown swordtail, at Threshing and manifests ice through the bond. One of the thirteen Threshing Day viewpoints. He is the jokester of the thirteen, which is the role the quadrant needs and rarely rewards. His account is the one that shows a cadet using humour as a survival strategy on a day that kills people.
Established Liam Mairi Dragon: Deigh. Role during Threshing: Bonded Deigh, a red daggertail, at his own Threshing. Deigh is killed by a wyvern at the Battle of Resson, and Liam dies with him, which is the series' clearest demonstration that no rider survives the loss of their dragon. One of the thirteen Threshing Day viewpoints. He is the kindhearted protector of the thirteen and one of the few riders in the series who dies on the page. His record carries the most weight of the thirteen, because a reader who has finished Fourth Wing knows how the story ends and comes back to the beginning anyway.

Spoilers: Iron Flame

This section contains material from later in the series.

Story nodes, gated at Iron Flame

Established Imogen Cardulo Dragon: Glane. Role during Threshing: Bonded Glane at her own Threshing. In the novels the pairing is established in Iron Flame, where Glane is named and coloured. One of the thirteen Threshing Day viewpoints. She is the marked one who hates Violet on sight for her mother name and ends up training her. Imogen is the collection one clear look at a rider whose family was executed by the institution she is now conscripted into.
Established Sloane Mairi Dragon: Thoirt. Role during Threshing: Bonded Thoirt and manifested the rare siphoning signet. Siphoning is the ability that makes her final act in Iron Flame possible, since it lets her move power from one person into something else entirely. One of the thirteen Threshing Day viewpoints. She enters the quadrant in Iron Flame believing Violet may have been responsible for her brother death. She is the newest rider of the thirteen and the one carrying the most family history into the valley, which makes her chapter the bridge between the collection and the novels.
Established Aaric Graycastle Dragon: Molvic. Role during Threshing: Entered the Riders Quadrant in Iron Flame as a first-year under the name Aaric Graycastle and bonded Molvic. His exact Threshing is not described in the novels. One of the thirteen Threshing Day viewpoints. His true identity as Prince Camlaen Aaric Tauri is one of Iron Flame quieter reveals. He is the restless royal of the thirteen, and his account is the only one written by someone who chose the quadrant when he could have avoided it.

What the collection unlocks

Spoilers: Threshing Day

This section contains material from later in the series.

The collection hands over a death that Fourth Wing spends its entire length preparing, told from the side of the rider who lived it. It also confirms what happened to Brennan Sorrengail in the years before the main series, and gives a first-person account of the ambush that shaped the marked ones before they ever reached the quadrant.

Several of the bonding stories reframe choices the main novels present as settled: why a dragon waited, why one crossed a valley to reach a particular cadet, and what a dragon sees in a rider who has not yet done anything worth seeing.

Treat anything you read about the individual stories elsewhere as a community report unless it comes from the book itself. Only the opening frame title is attested in reachable official material.

Sources

Questions people actually ask

Thirteen stories, one per character, each covering that character's own Threshing Day. The stories are arranged by year, so the collection moves through the ritual across more than a decade of in-world time.

Xaden Riorson, Brennan Sorrengail, Dain Aetos, Sawyer Henrick, Sloane Mairi, Imogen Cardulo, Ridoc Gamlyn, Aaric Graycastle, Mira Sorrengail, Liam Mairi, Bodhi Durran, Rhiannon Matthias and Garrick Tavis.

She is not one of the thirteen viewpoints. Her Threshing is already covered in Fourth Wing, and the collection deliberately steps sideways into the riders whose day was never shown.

224 pages in the US hardcover and ebook listing. Earlier pre-publication figures of 176 and 179 pages circulated before release and are superseded.

The US edition is ISBN-13 978-1682818084, ISBN-10 168281808X, published by Red Tower Books on September 29, 2026.

Yes. The collection carries its own spoiler warnings for a reason, and at least one story revisits a death that Fourth Wing spends its whole length preparing for. The publisher recommends reading it after Onyx Storm.

The deluxe first edition hardcover carries sixteen full-colour interior pieces by Joe Requeza, colour endpapers and sprayed edges, and was sold in the US and Canada while supplies lasted. The standard hardcover is plain black with silver spine type.

1 further answer is held back because it gives away a plot point. Raise your spoiler setting in the header to read it.

Ready to be chosen?

Our own Threshing runs in about three minutes. No account.

Enter the Vale

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