Book 4 Xaden
I have theory for Xaden in the next book/s when it comes to Violet.
Theophaine states at the end of Onyx Storm that Violet will keep her love and Xaden, or what is masquerades as if she were to turn, and that got me thinking. Rebecca has already said Xaden will be the villain in the next book, so I wonder if instead of love Xaden will fall into an obsession for Violet.
Love is letting someone go even when you want to keep them, because you care more about their happiness and wellbeing. I think Xaden will masquerade with love for Violet, when really, he just has an insane obsession with her. I think this could lead to really awful consequences like killing off Violet's squadmates, which easily tracks with the popular theory (I subscribe too as well) that the person who we love that will die in book 4 will be killed by Xaden (who I definitely think will be Rhiannon or possibly Ridoc).
Also, there's that dream Violet (Xaden) has in Iron flame where Berwyn basically tells them that they are going to "tear down the wards for love" AND THIS HAS NOT HAPPENED YET😭
My theory is that Xaden thinks he's in love, but as he loses all the pieces if his soul, forms a more selfish, destructive obsession with Violet, that leads to him tearing down the wards.