Onyx Stormpacked a lot into its story, and some readers might have missed the section about the unnamed “brother” Xaden refers to being turned into a venin. Theending ofOnyx Stormwas messy, to say the least, and it ended on a cliffhanger, lobbing a few huge questions at readers before coming to a close. One of the biggest is that a character, seemingly a major one, hasturned venin inOnyx Storm, whether after being forced or of their own volition, but their identity will apparently not be revealed untilthe fourthEmpyrean Seriesbook. We do know a few things about the person who turned, though:
It’s not much to go on, butit’s definitely enough to narrow down the list of potential candidates who fit the criteria; in truth, only a few characters match all the clues: three characters do, in fact. They may not have been one ofOnyx Storm’s major deaths, but if they did turn venin, it could end up being an even worse fate.

3Brennan Sorrengail
Violet’sOtherSibling
Of the choices of characters who fit the description given by the few hints Xaden’s POV chapter offered,Brennan Sorrengail is a strong option. In the scene, Xaden refers to the character as his “new brother,” and we know he means that metaphorically, as he has no siblings - at least, none that he has known: his newly discovered half-siblings don’t count. But before he refers to the unnamed character as his new brother, he uses the word “sibling” and he emphasizes it: “The bond between Berwyn and me is one that should never exist, and now that my Sage has anothersiblinghe can use against me…I’m screwed.”
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Onyx Storm
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It could be that Xaden is emphasizing the word “sibling” because he means it sarcastically, but when he later refers to his new brother, that phrase isn’t italicized. It’s a small clue, butXaden could literally mean a literal sibling - just not his.It’s also worth noting that he says “anothersibling,” considering Berwyn’ssilver-haired venin counterpart Theophaniehad already used a Sorrengail sibling, Mira, as a means to trap them. If that’s the case, Brennan is the only one who fits the “another sibling” role. He also knewXaden was venin and was trying to cure him, for months. And Xaden would obviously care enough about his well-being as his own friend and as Violet’s brother to try to save him.

2Garrick Tavis
Xaden’s Best Friend Has Disappeared
Another likely candidate who became venin at the end ofOnyx Stormis Xaden’s remaining best friend, Garrick Tavis. Like many characters, Garrick hasn’t gotten much development in the previous books but played a larger role inOnyx Storm, seeming to step into the void left by Liam Mairi. When Garrick is poisoned by Faris, Violet, in the narrative, describes Garrick as Xaden’s “best friend.” They’re clearly close enough that Xaden would hate seeing him go down the same venin path. Considering Garrick was one of the few people trusted with the secret that Xaden was turning venin and saw how he struggled, it would also feel like a bit of a heartbreaking betrayal to Xaden, which comes through in the scene.
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It’s alsonot clear where Garrick is at the end ofOnyx Storm. He’s one of four riders who are mentioned missing at the end of the book, along with Xaden. That seems notable.Garrick’s distance-wielding second signet revealed inOnyx Stormwas tapped out, but unless Garrick was dead, only something major would have kept him from returning after the fight. Turning venin would certainly do that.

It’s not clear why Imogen’s chapter was included, but it could be that it’s just in there to offer a clunky way to make a future reveal that Garrick has become venin more dramatic and impactful.
It’s entirely possible that Imogen’s POV chapter, which came out of left field, wasn’t about killing off Quinnbut about hinting that Imogen was finally going to tell Garrick how she felt about him. It’s not clear why Imogen’s chapter was included, but it could be that it’s just in there to offer a clunky way to make a future reveal that Garrick has become venin more dramatic and impactful. The chapter doesn’t really make much sense, otherwise - all due respect to Quinn, but she was one of the many side characters who could have been killed off at any time in any way with zero impact on the plot.

1Bodhi Durran
He Never Wanted To Be The Heir Of Tyrrendor
The third and final choice for who turned venin at the end ofOnyx Stormis, of course, Bodhi Durran. Going back to the choice of words Xaden uses - “sibling”, “new brother” - as Xaden’s cousin and his lookalike, Bodhi is the closest thing Xaden does have to an actual brother (again, Xaden’s new half-brothers don’t count here). It would rip Xaden apart to see Bodhi, of all people, walk the path of the venin. Bodhi becoming venin would also arguably feel most like a betrayal to Xaden, especially as he’d looked to Bodhi to be Tyrrendor’s heir once he, Xaden, was completely turned to the dark side.
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That’s exactly why Bodhi may have become venin onOnyx Storm, though. He was adamant that he had no desire to replace Xaden as Tyrrendor’s duke. As he tells Theophanie when she teases him with the crown, “I’m doing exactly what I’ve always wanted - protecting my cousin, my province.” It wouldn’t be out of the question that Bodhi would turn venin in an attempt to save Xaden, however ill-advised, oreven sacrifice himself in a misguided attempt to leave Xaden with no choice but to fight the urge to fully turn.Whether it’s Bodhi, Garrick, or Brennan, though, it’s a shocking development that will have a big impact moving forward.