Warning: SPOILERS ahead for Onyx Storm by Rebecca Yarros.

Onyx Storm’s shocking ending has led to many fan theories aboutthe nextEmpyrean Seriesbook, and the saddest has to do with Tairn and Sgaeyl’s mating bond. While Violet and Xaden’s relationship is the central focus ofThe Empyrean Series,Tairn and Sgaeyl are equally important toFourth Wingand its sequels. It’s their connection as mates that brings Xaden and Violet closer together — and gives them the ability to communicate mentally throughout Rebecca Yarros' books.Onyx Storm’s endingsees Violet and Xaden separated, however, leaving readers to wonder how their dragons will deal with their newfound distance.

Among the manyquestions I had afterOnyx Storm’s endingis where Sgaeyl is, as it’s not clear whether she’s still with Xaden or closer to Tairn. She and Xaden come to some sort of agreement during his POV chapter, but Xaden’s plans seem to involve giving in to the venin. Given that Berwyn wants Sgaeyl dead at the end ofOnyx Storm— and venin riders don’t seem as affected by losing their bonded dragons — it’s possible Sgaeyl and Xaden also part ways. However,another theory posits that Sgaeyl and Tairn broke their mating bond, and I hope it isn’t true.

The Empyrean Series book covers on sparking fire background

Onyx Storm Theory Reveals That Tairn & Sgaeyl Broke Their Mating Bond At The End Of The Book

This Would Explain Tairn’s State After The Final Battle

The end ofOnyx Stormis chaotic, as Violet has no recollection of the book’s final 12 hours,courtesy of Imogen wiping her memories. Violet and Xaden seemingly get married within that timeframe, and Xaden also leaves Aretia behind. He tells Violet not to look for him, butOnyx Stormdoesn’t reveal where Sgaeyl is. When Violet reaches for Tairn, she notes “the bond feels foggy.” And Andarna tells her, “He needs a cycle of rest to recover.” It’s implied that he’s recuperating from his and Violet’s confrontation withthe silver-haired venin, Theophanie. However, I’m not certain this is the case.

This might be the only way for Sgaeyl to remain with Xaden, as mated dragons need to see one another regularly.

Fourth Wing, Onyx Storm, Iron Flame by Rebecca Yarros

After all, Tairn is conscious and seemingly fine when Violet kills Theophanie; he’s merely stuck in the net the venin uses to trap him.There’s no clear reason Tairn should be so worn down afterOnyx Storm’s final battle, unless something significant happened during the 12 hours Violet has no memory of. And with Sgaeyl nowhere to be found, it seems possible that the two broke their mating bond. This might be the only way for Sgaeyl to remain with Xaden, as mated dragons need to see one another regularly — and running off with the venin would prevent that from happening.

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After Onyx Storm’s cliffhanger ending, readers have begun to put together many convincing theories as to what will happen next in the Empyrean Series.

Xaden and Sgaeyl are pretty cryptic when discussing their plans at the end of the book, but Xaden’s disappearance suggests he’ll leave with the venin. Sgaeyl doesn’t initially have much confidence in whatever he intends to ask of Violet and Tairn. This is a clue that they’ll need to agree to a major sacrifice. Sgaeyl seems more focused on Violet’s consent, so it’s hard to say if this discussion has to do with Tairn’s bond with Sgaeyl. However, it certainly seems possible, especially given his surprising state in the final chapter of the book.

A cover image of Onyx Storm on an illustrated background of dragons and mountains

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And while the mating bond between dragons is supposed to be the strongest connection inThe Empyrean Series,Sgaeyl has put Xaden before Tairn in the past. She keepsXaden’s second signeta secret from Tairn inIron Flame.And she remains with Xaden when he turns venin, despite Tairn consistently referring to him as “the dark one” and claiming he’s lost. I think there’s enough evidence to at least consider that Tairn’s bond with Sgaeyl is broken. Plus, Andarna’s arc inOnyx Stormlays the groundwork for it, as it establishes that dragons can break powerful bonds.

The covers of Fourth Wing, Onyx Storm, Iron Flame, and a book with a fiery 4 on it

Andarna’s Onyx Storm Story Sets Up This Tragic Tairn & Sgaeyl Twist

It’s The First We Hear Of Dragons Using Their Magic To Break Bonds

Although it doesn’t seem related at first glance,Andarna’s story inOnyx Stormmay have set up Tairn and Sgaeyl breaking their mating bond. When Leothan shows up to fire Aretia’s wardstone, he convinces Andarna to spend time among the irids — and to break her bond with Violet to do so. Up until this point,The Empyrean Seriesonly discusses broken bonds in relation to riders and dragons dying. However, Leothan tells Andarna that she’s capable of severing her bond with Violet using her magic. He treats this like it’s the most obvious thing in the world.

I know mating bonds are different from the bonds dragons form with their riders, but Leothan’s words confirm that dragons can use their magic to break powerful connections.

Onyx Storm book cover on dark cloudy background

I know mating bonds are different from the bonds dragons form with their riders, but Leothan’s words confirm that dragons can use their magic to break powerful connections. This would likely kill their rider if they were their sole dragon, but it’s not clear whether dragons can willingly sever their own mating bonds. A dragon’s mate dying allegedly kills them, but that doesn’t necessarily mean dragons can’t choose to leave their mate.Fourth Wingleaves questions about how the dragons' mating bond works, which meanswe can’t rule out the possibility that Tairn and Sgaeyl can sever theirs.

What Tairn & Sgaeyl No Longer Being Mates Would Mean For The Next Empyrean Book

This Twist Would Make The Distance Between Violet & Xaden Even Greater

If the theory that Tairn and Sgaeyl’s mating bond is broken proves true,it will have major consequences in the nextEmpyrean Seriesbook. With Xaden and Violet being separated,Onyx Storm’s sequel is already shaping up to be the darkest and bleakest addition to the series yet. Tairn and Sgaeyl no longer being bonded would make the distance between Violet and Xaden even greater, as it would remove their ability to communicate mentally or feel the other’s presence, even when they’re close to one another.

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This twist would also affect Tairn deeply in the next book, as I don’t believe the dragons would choose to break their bond lightly. Given that they still love each another, Tairn would struggle with Sgaeyl’s absence, even without the bond in place. Just as he comforts Violet and Andarna throughout the first threeEmpyrean Seriesbooks, they’d need to support him through the next novel. And the absence of Sgaeyl could make Tairn reckless, making me think that myfears of Tairn dying in the nextFourth Wingsequelaren’t totally unfounded.

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

This Onyx Storm Theory Makes Sense, But I Really Hope It Isn’t True

It Would Make The Coming Sequels Even More Tragic

TheOnyx Stormtheory that Tairn and Sgaeyl’s bond is broken makes a decent amount of sense, but I still hope that it isn’t true. Tairn and Sgaeyl are among the most consistent characters inThe Empyrean Series,and their love feels like a constant in Yarros' story. Upending that would make the next book so much more devastating, and we’re already in for a rough time with Violet and Xaden being separated. I don’t know that I can handle Tairn and Sgaeyl being in just as much pain, even if they reunite at some point afterOnyx Storm.

Onyx Storm Book Cover