The release ofOnyx Stormon January 21 will mark one of the biggestfantasy book debuts of 2025, as readers have been eagerly anticipating thenextFourth WingsequelsinceIron Flamehit shelves. GivenIron Flame’s twist ending, that’s not surprising. But with more than a year between books two and three ofThe Empyrean Series,readers' memories might be hazy when it comes to the first two installments. There’s a lot toremember fromFourth WingandIron Flame,as Rebecca Yarros' world is expansive and complex.

Some developments from the first two books are likely to be more important than others heading intoOnyx Storm,which will reveal what becomes of Basgiath and its cadets on the heels ofIron Flame’s venin battle. We know fromOnyx Storm’s excerptand synopsis that Basgiath’s cadets will return to the institution and ready themselves for war. But as with all theEmpyrean Seriesbooks, it’s inevitable they’ll face unexpected twists and turns. Needless to say, readers should refresh their memories when it comes toFourth Wing’s andIron Flame’s biggest revelations.

Fourth Wing by Rebecca Yarros on purple background with dragon

10Violet’s Father Was Immersed In Research Before His Death

His History As A Scribe Will Likely Be Important In Onyx Storm

Violet Sorrengail’s father is dead by the timeFourth Wingbegins, but his presence is felt throughout the first twoEmpyrean Seriesbooks. Violet reveals that her father died of heart problems early inFourth Wing,though there are many theories suggesting his death wasn’t due to natural causes. Regardless of whether these prove true,the fact that Violet’s dad was a scribe seems certain to come up again inOnyx Storm.Mr. Sorrengail’s research is mentioned throughout the first two books, and it’s noted that it involved Feathertails.

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Given that Feathertails remain mysterious heading intoOnyx Storm,it’s possible the sequel will answer some of readers' biggest questions about the young dragons. This could be done through Mr. Sorrengail’s research, though Violet’s father may have been studying more than juvenile dragons. His note to Violet inFourth Wing— and Lilith’s part in Navarre’s secret-keeping — suggest he also knew about the venin and wyvern.His research could hold answers that Violet and Xaden need inOnyx Storm.

Onyx Storm by Rebecca Yarros Book Cover

9The Venin General From Fourth Wing Is Interested In Violet’s Lightning Signet

The Villains Want Violet’s Power

Fourth Wing’s venin Sage — who reveals he’s actually a general at the end ofIron Flame— is extremely interested in Violet and her lightning signet throughout the first two books. Although the venin never hesitate to kill humans or dragons,their leader commands them to leave Violet alive during the secondEmpyreanbook. Several of them also note his interest in her lightning wielding power, one of themost powerful signets inFourth Wing.

Violet learns to control her signet better throughoutIron Flame,making her even more valuable to both sides inOnyx Storm.

Custom image of the original copy of Fourth Wing by Rebecca Yarros with blue electricity around it.

With the venin’s leader potentially still alive inOnyx Storm, it’s worth remembering all the attention he gives Violet and her power in earlier books. Violet learns to control her signet better throughoutIron Flame,making her even more valuable to both sides inOnyx Storm.Andthe third book could reveal the villains' true intentions for Violet and her ability, answering one of the biggest questions left over afterIron Flame.

8Tairn’s Former Rider Sacrificed Himself To Save Brennan Sorrengail’s Life

Naolin’s Choice May Be More Important Than It Seems

Tairn’s former rider, Naolin, sacrifices everything to save Brennan Sorrengail’s life— a decision that facilitatesFourth Wing’s endingtwist. It’s not entirely clear how or why Naolin does this, and the other characters don’t reveal much about him. Brennan tells Violet that doing so “cost him everything,” but that isn’t necessarily the same as dying. Tairn seems reluctant to discuss his former rider, leaving readers to speculate on whether he turned venin saving Brennan or used some other secret to resurrect him.

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Given the mysterious rune on Brennan’s hand and questions surrounding his return,it seems likely Naolin will come up again in futureFourth Wingbooks. Additionally, losing Naolin informs much of Tairn’s arc throughoutThe Empyrean Series.It’s part of the reason he’s so fiercely protective of Violet, as he doesn’t want to lose another rider. This makes Naolin’s fate far more important than it seems, so it’s worth keeping in mind duringOnyx Storm.

Custom image of the special edition Fourth Wing book with a silhouetted dragon and fire in the background.

7Dain Is Earning Violet’s Forgiveness (& Angry With His Father)

Onyx Storm Is Poised To Continue His Redemption Story

Dain betrays Violet and the Marked Ones at the end ofFourth Wing,though he doesn’t realize his father’s plans for them when they reach Athebyne. This doesn’t prevent Violet from being angry with him, as he uses his signet on her without consent. However, the two begin working through their problems after Dain saves her from Vice Commandant Varrish’s torture duringIron Flame.Violet still doesn’t forgive Dain completely, but the two are on more civil terms by the end of the second book. AndOnyx Stormis poised to continue Dain’s redemption arc.

Dain chooses to leave Basgiath and join the rebellion, setting him up to be a hero in futureEmpyreanbooks. He has a long way to go when it comes to proving himself, but he’s on the right path afterIron Flame.He’s also angry with his father for lying about the venin, and that hasn’t been addressed just yet. With the cadets returning to Basgiath,it seems likely that Dain will face Colonel Aetos whenOnyx Stormdebuts.

The cover of Onyx Storm by Rebecca Yarros with the Iron Flame and Fourth Wing covers enlarged as the background

Iron Flame Reveals He’s An Inntinnsic

Iron Flameconcludes with several big twists regarding Xaden, one of which is the fact that he has a second signet. Because Sgaeyl was also bonded to his grandfather, her connection to Xaden grants him a second ability.He’s a type of Inntinnsic, but he’s forced to keep this quiet, as such a power is a death sentence at Basgiath. Xaden’s second signet allows him to read other people’s intentions, explaining how he’s able to suss out threats to his movement.

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Xaden’s second signet is only known by Violet and their dragons heading intoOnyx Storm,but other characters could learn the truth in the next book.This power could also prove a problem if Xaden isn’t able to stay in control, so that’s a threat to watch out for during the rest ofThe Empyrean Series.

Onyx Storm book cover on dark cloudy background

5Navarre’s Wards Don’t Completely Block Out The Venin

Jack Barlowe Reveals They Can Channel To Some Extent Within The Wards

Jack Barlowe returns as a venin inIron Flame,undoingFourth Wing’s most satisfying moment, and this twist reveals a harsh truth about Navarre’s wards. While Violet successfully restores the wards surrounding Basgiath inIron Flame,Jack’s existence presents a problem for her and her friends. As Jack tells her during theFourth Wingsequel, the wards aren’t foolproof against the venin. While their powers shouldn’t work beyond them,Jack is proof that venin can be made within the wards.

Just because Navarre is able to restore its wards at the end ofIron Flamedoesn’t mean that its people are in the clear.

Onyx Storm by Rebecca Yarros on a smoky background with red veins

Jack also tells Violet that venin can channel to some extent while inside the wards — enough that it allows them to survive.Onyx Storm’s excerpt suggests that Basgiath will be breached again in the third book, and Jack’s sentiment could explain how. Just because Navarre is able to restore its wards at the end ofIron Flamedoesn’t mean that its people are in the clear. There could still be venin lurking on their side of their borders, a worrying prospect for Violet and her friends.

4Iron Flame’s Ending Battle Exposed Navarre’s Lies

People Will Likely Know About The Venin & Wyvern In Onyx Storm

The final battle inIron Flameis big enough thatNavarre will no longer be able to keep the venin and wyvern a secret. This is important heading intoOnyx Storm,as it means many of the kingdom’s citizens will learn about the lies their leaders have been feeding them. Such revelations could lead to political unrest in the next novel, assuming Navarre’s leadership doesn’t find new ways to avoid accountability.

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Considering they need the support of the rebellion’s dragon riders,it seems unlikely Navarre’s leaders will be able to deceive their citizens again. This raises questions about how the public will respond to the news of the venin and wyvern existing. It could lead to changes in Navarre’s government and military structure — and even if it doesn’t have this much of an impact, it will certainly give them a lot to contend with inOnyx Storm.

Cropped cover of Onyx Storm: image of a dragon silhouette against a bright sun

3Andarna Is The Seventh Breed Of Dragon

Onyx Storm Must Answer Questions About Andarna’s Kind

Andarna is a mystery from the moment she’s introduced, but her growth inIron Flametakes her from being a Feathertail to what Violet initially assumes is another black dragon. Violet realizes her error at the end of the second book, when Jesinia reveals that seven breeds of dragon are needed to raise the wards.Andarna is the seventh breed of dragon— something Navarre isn’t aware exists — and she is the leader of her own Den. This explains why she waited so long to hatch, as well as why she was able to bond with Violet.

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ThisIron Flamereveal is huge, and it doesn’t get a ton of attention before the book comes to a close.It seems inevitable thatOnyx Stormwill expand on what Andarna’s true nature meansforThe Empyrean Series. There are pressing questions the sequel needs to answer, like what happened to the rest of Andarna’s kind. It’s also likely that Violet won’t be able to keep Andarna’s secret for long, which could lead to tensions between dragons and humans.

A collage of a black dragon over the official artwork for Onyx Flame

2Violet & Xaden Chose The Wards At Basgiath Over The Wards At Aretia

Brennan & Xaden’s Revolution Will Need To Move

Violet and Xaden are forced to choose between raising the wards at Basgiath over the wards at Aretia, and this will have consequences inOnyx Storm.With Aretia not being properly protected,it seems probable that Xaden and Brennan’s revolution will need to move. Melgren asks the cadets that fled Basgiath to return at the end of book two, and given the ward situation, they might bring the gryphon riders and rebellion leaders with them.

Navarre’s leaders will probably clash with the rebellion heads, which could lead to some interesting conflicts inOnyx Storm.

Every-Type-&-Color-Of-Dragon-In-Fourth-Wing-Explained

This meansBasgiath could look quite different in the thirdEmpyrean Seriesbook. Tensions are likely to be high if dragon riders and gryphon riders are forced to mingle, as those who stayed at Basgiath aren’t as familiar with outsiders. And Navarre’s leaders will probably clash with the rebellion heads, which could lead to some interesting conflicts inOnyx Storm.

1Xaden Is Now A Venin After Iron Flame’s Ending

Xaden’s Predicament Will Be A Major Storyline In Onyx Storm

The biggest twist fromIron Flame’s ending is that Xaden is now a venin, and this will be a major storyline inOnyx Storm.Yarros’Instagramteases confirm as much, revealing that Xaden and Jack will discuss Xaden’s transformation, as well as the fact that Violet will be determined to “save him.” So, if there’s one moment fromIron Flamethat readers should revisit prior toOnyx Storm,it’s Xaden’s chapter. Watching him turn for love is heart-wrenching, but it’s definitely going to be important in the sequel.

It’s not clear how Xaden’s change will affect his bond with Sgaeyl, though her anger inIron Flamedoesn’t bode well for the pair. Xaden becoming venin also sets up more relationship problems for him and Violet, which could keep them apart inOnyx Storm. Only time will tell if they’ll find a way to reverse Xaden’s condition, which has readers on edge ahead of the next book.

Onyx Storm

Violet Sorrengail faces new political intrigue and battles old enemies while uncovering the secrets of her second signet. As she strives to save Xaden from venin corruption, her relationships with allies and dragons are tested, leading to intense confrontations and unexpected revelations in a world of dragons and magic​.