Rebecca Yarros’Onyx Stormrevolves closely around Xaden’s transformation into venin, especially afterIron Flame’s cliffhanger ending—a detail most readers had a hard time adjusting to, even with the year wait between theEmpyrean Series' book releases. Clearly, Xaden turning venin was the biggest concern going intoOnyx Storm, and while his character arc was trending towards a tragic end, many had hopes he would be cured in Yarros' third novel. Unfortunately, this was not the case, and at theend ofOnyx Storm, Xaden draws upon more power and completes his venin transformation, becoming an asim.
Onyx Stormreveals more about the veninthrough Xaden’s character, but as readers begin to witness his daily struggle to resist his venin powers, it becomes glaringly obvious this wasn’t a path that was absolutely necessary. Both inIron FlameandOnyx Storm, Xaden channels more power from the earth to save someone he loves—in this case, both Violet and Sgaeyl. However, inIron Flame, it was not his sacrifice that saved Violet, but General Sorrengail’s. This realization already puts Xaden’s situation in a depressing light, but another majorOnyx Stormreveal makes it even more tragic.

Iron Flame Already Showed Xaden Didn’t Need To Turn Venin To Save Violet
Violet’s Mother Sacrificed Her Life To Save Her
At theend ofIron Flame, Xaden makes the decision to become venin when he realizes Violet is nearing burnout when imbuing the wardstone—as there was nothing he could do to help while in the hands of the venin sage. It’s at this point in Xaden’s bonus chapter that he decides to draw power from the earth—even against Sgaeyl’s warning—choosing Violet over everything and anyone else. However, what Xaden didn’t know was that Violet’s mother had already given her life in order to spare Violet’s,effectively making Xaden’s decision to turn venin a pointless sacrifice.
However, an argument could be made that Xaden turning venin helped to kill the venin sage, but evenOnyx Stormreveals that his earlier attempts to kill Berwyn inIron Flamefailed.

While Xaden’s decision to turn venin likely did help to save lives by removing the venin sage from the battleground,it was really the raising of the wards that ended the battle entirely. Knowing this happened just minutes after he turned venin, there’s a chance he could have held out and avoided this fate altogether. However, an argument could be made that Xaden turning venin helped to kill the venin sage, but evenOnyx Stormreveals that his earlier attempts to kill Berwyn inIron Flamefailed.
Onyx Storm Confirmed That The Sage Is Still Alive
Xaden Is Incapable Of Killing Berwyn
Xaden’s POV chapter at the end ofOnyx Stormreveals that the venin sage he tossed into the ravine at Basgiath, and who he thought was dead, is in fact alive—and has apparently been waiting for Xaden the entire time.Iron Flameeven hints at Xaden’s fear of the venin sage surviving, and it’s likely that his feeling of uneasiness was actually a sign that the bond between Berwyn and Xaden was not yet broken. After the two are reunited inOnyx Storm,Xaden comes to realize he is incapable of killing or harming Berwyn himself.
“I keep watching the river like it’s going to pop back up, even though I know he’s miles downstream by now.”
—Iron Flame, Chapter 65
This major revelation inOnyx Stormmakes Xaden’s sacrifice inIron Flameeven more tragic, as he gave up his humanity in order to save Violet and kill Berwyn—both of which he did not accomplish.Onyx Stormleaves readers with a heavy sense of hopelessness, especially now that Yarros has confirmed his sacrifice was, apparently, all for nothing. However, there’s a chance Xaden is holding onto the last of his humanity through his strong bond with Violet—and hopefully his sacrifice to turn venin will regain a sense of purpose in thenextFourth Wingbook.
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.