If you consider yourself a modern bibliophile, you'd be hard pressed to miss the Fourth Wing wave that has swept through the zeitgeist.

Now months on from the release of third book in the series, Onyx Storm, many are beginning to ask questions about when we'll see the next Fourth Wing book. Collectively, the series is known as the Empyrean Series; and author Rebecca Yarros has been transparent in revealing there will be five books in the collection.

With the first, Fourth Wing published in April of 2023, Iron Flame in November 2023 and Onyx Storm in January 2025, speculation around book four is rife. While we wait for more details on the series to be confirmed, here's what we know (and what we don't) about the release date and plot.

Rebecca Yarros is back at her desk

The latest (very exciting) update came via Instagram, courtesy of Yarros herself. Alongisde a carousel of photos, the author wrote:

“When I turned in Onyx Storm to the printer a year ago, I promised myself and my family I would take a year off. In that year ‘off’, I wrote and edited a full graphic novel, started another, plotted and started writing a new contemporary novel, and signed about 120k tip-ins. Yeah, I don’t sit still well.

“But now it’s been a year, and I’m back at the desk full-time, learning how to juggle my priorities all over again [and] it seems like a good time to step away from socials for a bit. I love IG, but it definitely has the power to drain my time and energy, which are needed elsewhere right now.”

We'll admit, she didn't exactly confirm that it's the fourth Emyprean book the she's working on, we're staying positive as we fill in the blanks here.

When can we expect it to come out?

We're going to be waiting at least a year or two – with some speculating that it could come in 2027.

Based on a comment Rebecca Yarros left on TikTok, she plans to begin plotting book four of the Empyrean series in September or October of 2025.

In the comment from August 2025, Yarros said: "It's not up there yet. Probably in the next six weeks or so. I like to plot one project ahead, but I'm still in the thick of it with plotting the contemporary!"

So, while no ink has hit the page as of yet, at least we know that there's a plot coming together as we speak. And the additional planning time is likely to win over some fans who felt that Iron Flame was not as strong as Fourth Wing, for example, due to a rushed production process after the first book blew up. Perhaps a lengthier writing and editing timeline will be welcomed.

What is it called?

Right now, the book is as-yet untitled.

The title reveal will be key to guessing what takes place in the next book, however. As we know, Onyx Storm refers to the power released by Xaden when he gave into his Venin transformation in order to protect the squad at the conclusion of book three.

What plot details do we have?

We'll be honest, plot details are scant.

Yarros has teased a few of the book's potential plot points at events promoting the series. Speaking in Los Angeles, for example, the author has said that "someone you love won't make it in book four". The Empyrean Series isn't known for giving characters "plot armour", but knowing someone the audience loves will die in the next book just makes me want to know even more.

At the same event, Yarros - who has a playlist for every book - revealed a few songs from the book four track list. All three were from Taylor Swift's album The Tortured Poets Department, including Down Bad, I Can Fix Him, and But Daddy I Love Him.

Where will the plot pick up from?

The as-yet-untitled fourth Emyprean book will pick up after the dramatic cliffhanger of Onyx Storm. Look away now if you don't want spoilers.

At the conclusion of the tale, Violet awakens at Riorson House with her brother, but with no memory of the epic battle that took place.

What she does know, however, is that her memory was taken by Imogen, and that she did so at Violet's own request. She also notices some new accessories on her person that she doesn't remember picking up. Namely, a wedding ring on her finger and a marriage certificate to Xaden.

Unfortunately, the honeymoon between the pair will probably have to wait. During the battle to protect Aretia at the conclusion of Onyx Storm, Xaden gives in and becomes Venin in an attempt to take out as many Venin as possible during their incursion.

The cliffhanger that still leaves us reeling sees Xaden hint that someone he trusted has joined him and also turned Venin, with no names revealed.

Will the Empyrean Book four be the last in the series?

Thankfully, no. While most epic fantasy stories play themselves out in three, maybe four instalments, Yarros has stated more than a few times that the Empyrean Series is set to be a five-book run. So we have at least two more to look forward to right now.