‘Threshing Day’: Details You Missed in the ‘Fourth Wing’ Collection

Happy Threshing Day!

OK, it’s not actually Threshing Day, but Tuesday is the day Rebecca Yarros released her new “Fourth Wing” book titled “Threshing Day.”

No, it’s not book four in the “Empyrean” series, which readers have been anxiously awaiting since “Onyx Storm” was released in 2025. It’s a collection of the stories of riders from the “Fourth Wing” universe on their Threshing Days, when they bond with their dragons in their first year of training at Basgiath War College.

Protagonist Violet Sorrengail doesn’t have a story in the collection, as her Threshing Day appeared in “Fourth Wing.” Instead, Yarros offers the perspectives of people around Violet, unveiling new lore about the riders and their dragons.

The stories have major ramifications for Yarros’ beloved romantasy series, including how dragons bond and hints at future romances.

Here are some of the most important details you might have missed in “Threshing Day.”

Multiple points of view

The new book includes the story of 13 Threshings, though some of those stories take place on the same day. For instance, Xaden Riorson and Garrick Tavis experience Threshing Day together, and their chapters follow the day from their respective perspectives.

Notably, Yarros includes a note at the top of the book that says, “The following text has been faithfully transcribed from Navarrian into the modern language by Colonel Valin Kaori and Lieutenant Ellery Mynna, professors of Dragonkind at Basgiath War College.”

That note differs from those included at the start of the “Fourth Wing” novels, which are transcribed by the scribe Jesinia Neilwart. Scribes have been revealed to be unreliable narrators throughout the events of the “Empyrean” series, while Dragonkind professors have not, making “Threshing Day” more trustworthy than other books in the series.

Yarros confirmed at a book release event in Denver that readers can trust the narration in “Threshing Day,” unlike in the rest of her series.

“It tells you that yes, this is a faithful first POV,” she said. “You guys can trust what happens in this book.”

How Threshing works

Although readers saw Violet bond her dragons, Tairn and Andarna, in “Fourth Wing,” much about the actual process remained a mystery.

“Threshing Day” broke down how the process works in more detail. First, several of the riders describe feeling a tugging in their chests that leads them to their dragons, as if they are calling to them.

Each rider also sheds blood during Threshing. Some scratch themselves on trees or get in a fight before they bond, but in Ridoc Gamlyn’s case, blood seemed to appear out of nowhere: “I note a twinge in my knee that, yep, is bleeding. Huh. I must have landed on a twig or something back there.”

Yarros doesn’t explain why each rider bleeds during their Threshing, but dragons frequently refer to bloodlines as sources of power in the “Empyrean” series.

Several of the riders also express a need or desire before bonding, which is later fulfilled by the signet power they develop. Brennan Sorrengail thinks to himself how important menders are moments before he bonds his dragon and goes on to become a powerful mender. Imogen Cardulo wishes she could take back something she said, and then develops the power to erase memories (more on that later).

The correlation suggests that signet powers align with a rider’s temperament or desires, though we’ll have to see how Yarros explores that concept down the line.

Rebel dragons

Many of the riders featured in “Threshing Day” are children of rebels who fought against Navarre, whom readers learned in “Iron Flame” and “Onyx Storm” are secretly bonding with dragons that previously bonded with their direct family members. The practice is forbidden in Navarre because it can allow riders to develop multiple signets, creating a power imbalance.

In the first chapter of “Threshing Day,” Professor Colonel Thadeus Palme reveals that even the staff struggles to tell dragons apart, creating the potential for confusion.

“I have found that no artist has flawlessly depicted every distinguishing mark of a dragon, which makes telling descendants apart woefully difficult,” he wrote. “When in doubt, it is prudent to ask a cadet for the name of their dragon.”

Because humans rely on riders to trace dragons, the dragons can hide their identities. For instance, Imogen bonds with Glane, who is recorded as being 19 and having never bonded with a rider before her. Yet, Imogen knows that isn’t true because she met Glane as a child when she was bonded to her grandmother. Garrick’s dragon also indicates he is lying about his identity, though he doesn’t reveal who he is.

Human lies can also enable dragons to bond with their previous riders’ descendants. Xaden bonds with Sgaeyl, and in “Iron Flame,” he confesses to Violet that his dragon was previously bonded to his grandfather when she discovers he has a second signet. He didn’t answer Violet’s questions about how that was possible in “Iron Flame,” but in “Threshing Day,” Yarros reveals that Xaden’s public grandfather isn’t his biological grandfather. His grandmother had an affair with his great-uncle, and Xaden’s father was born from their affair. The public never knew Xaden’s true ancestry, which allowed him to bond with Sgaeyl.

Some dragons are also seeking out riders who want to overthrow Navarre and fight venin. On their Threshing Days, Xaden and Imogen tell Bodhi and Sloane Mairi that specific dragons are seeking them out because they want riders sympathetic to the rebel cause, confirming some dragons are playing an active role in the war.

Venin clues

As any “Fourth Wing” fan knows, “Onyx Storm” ended on a cliffhanger, with Yarros writing that an unnamed rider had joined Xaden as a venin.

Garrick and Bodhi are two of the likeliest suspects, and Yarros included hints that they could have turned in “Threshing Day.”

Garrick repeatedly expresses a willingness to sacrifice himself for the sake of others — particularly Xaden — throughout his chapter, a practice his dragon Chradh questions.

Bodhi, on the other hand, reveals that Xaden is his weakness, and he feels responsible for protecting him from abusing his power. Bodhi also worries he doesn’t have an identity outside being Xaden’s cousin, though bonding with his dragon Cuir seems to calm that fear.

Garrick may have turned venin in the hopes of protecting others, and Bodhi could have tried to carve his own path as a venin. Both riders’ loyalty to Xaden suggests they could turn to protect him as he travels down his dark path.

Mysterious moms

In addition to leaving clues about the venin, Yarros laid some groundwork for other aspects of the “Fourth Wing” series’ future.

Notably, multiple characters shared that their mothers’ whereabouts are unknown. Dain Aetos’ mother fled during the rebellion, leaving him with his father. She stopped writing letters to Dain a year before he started at Basgiath.

Garrick says he helped his mother escape Aretia before the rebellion fell. Neither Garrick nor Dain knows where their mothers are, which could mean they are lying in wait to help their sons when the time is right.

Similarly, Liam and Sloane’s mom is dead, but the dragons reveal she was called the Rune Master when she was alive. Liam says she had “unmatched skill with runes,” and Sloane’s dragon, Thoirt, tells her that she inherited her mother’s power. Sloane was revealed to be a siphon in the “Empyrean” series, but readers have yet to see how that might play into her prowess with runes.

Love is in the air

Although “Threshing Day” doesn’t have any scenes between Violet and Xaden, there are still some romantic plots that are developed in the text.

First, Yarros revealed that Imogen and Garrick have loved each other since childhood, with Garrick waiting anxiously for Imogen to arrive at Basgiath a year after him.

However, Imogen is holding Garrick at arm’s length because she has lost so many people she loves. In fact, when she shares an intimate feeling with him, Imogen immediately thinks to herself that she wishes she could remove the last 10 minutes from his mind. Considering she develops the ability to erase people’s minds shortly after, she may have been wiping her romantic expressions from Garrick’s mind without his knowledge, preventing their relationship from progressing.

Yarros also lays further groundwork for a romance between Sloane and Dain. Sloane hates Dain, as she blames him for Liam’s death. In “Onyx Storm,” though, they share multiple charged moments that have become fan-favorites for a potential enemies-to-lovers storyline, including an interaction where Dain forces Sloane to look at him by saying, “Eyes here.”

In “Threshing Day,” Yarros reveals it wasn’t the first time Dain said that to Sloane. When Sloane tries to sacrifice herself during Threshing, Dain saves her, breaking the rules of the Codex. They quarrel, and during the talk, Dain says to her, “Eyes here, Mairi,” to get her attention.

It seems likely Yarros will further explore Dain and Sloane’s relationship in future “Empyrean” works.