Threshing Day: Everything We Know About the Fourth Wing Spinoff

Rebecca Yarros's Threshing Day is already Amazon's best-selling fiction title before release. Here's everything confirmed about this Empyrean spinoff.

8/4/20262 min read

Threshing Day: Everything We Know About the Fourth Wing Spinoff

If you've read our reviews of Fourth Wing, Iron Flame, and Onyx Storm, here's news worth knowing: Rebecca Yarros has a new Empyrean release coming, and it's already dominating sales charts months before its release date.

What Is Threshing Day?

Threshing Day is a short story collection set within the Empyrean universe, told from the perspectives of beloved characters (and their dragons) from Basgiath War College. Unlike the mainline trilogy, which follows Violet's central narrative, this collection shifts perspective to give readers a wider view of the world and characters surrounding her story.

Release Date

Threshing Day is scheduled for release on September 29, 2026.

It's Already the Best-Selling Fiction Title on Amazon

As of late July 2026, Threshing Day topped Amazon's most-sold fiction chart despite not having released yet — pre-orders alone were enough to claim the top spot, which says a lot about how dominant the Empyrean fandom has become following Fourth Wing's breakout success and the news of its upcoming Prime Video adaptation.

Why a Short Story Collection Instead of Book Four

Spinoff collections like this typically serve a specific purpose in a long-running series: giving fans additional world content and character perspective without requiring the main trilogy's next installment to rush its pacing. For a series as sprawling as Onyx Storm made the Empyrean world become, a collection focused on side characters and dragons offers a way to expand the world further while the central narrative continues developing at its own pace.

Should You Read It Before or After the Main Series?

Given that it's built around "beloved characters" from Basgiath, I'd recommend reading Fourth Wing, Iron Flame, and Onyx Storm first if you haven't already — the short stories will carry far more weight once you're already invested in the characters and world the collection is drawing from, rather than serving as a starting point for newcomers.

Final Thoughts

With pre-orders alone enough to top Amazon's fiction chart, Threshing Day is shaping up to be one of the biggest romantasy releases of the year, riding the momentum of Fourth Wing's Prime Video adaptation news and the Empyrean series' massive, dedicated fandom. Mark September 29, 2026, if you're already caught up on the main trilogy.