Alex never came back to work for Poet.
If Alex never came back to New York to work for Poet, Nox would never have met him. That’s a given. But it would have a cascading effect on Nox’s story. The first notable entry would be Nox likely would never have moved out of the AU building. It was Alex’s encouragement that pushed Nox over the tipping point. Not to say that Nox wouldn’t later do this on his own, but it wouldn’t have been at this moment in the story.
Nox would have continued to live in the AU building, and he wouldn’t have needed his brothers to come out early since he wouldn’t be a mess because of the move (and because he met Alex).
Most of the Last Phoenix would be cut in half because there would be no Alex intermissions. Walker and Harvard wouldn’t have interrupted Nox, and he’d probably already have gone out with them. Nox would still have Drake and the twins by nature of the story. But Nox would still have the nightmare attached to him. His stressors would still be high.
The entirety of Taking Back Erebus would be gone. Which means Nox wouldn’t have the book to learn from. Ant might have gotten the book from Deacon before he gave it to Abraham (the master vampire of Las Vegas who Alex won the book from in a game with Deacon.) But if the book went to Abraham Nox wouldn’t have had it to learn about runes and likely Eddie wouldn’t have shown up.
Which probably means that Jesse found alternative plans for his sons. Probably even taking the boys with him. Which would mean the boys would have turned in a foreign country and likely been killed by the locals, but that’s not till the Fourth book.
The First Vestige would see a lot more problems in it. Several really big issues would come up. When Alec tests Nox by trying to Dominate him, Nox likely would have given in, the predominate reason he didn’t was because Alex would be pissed at him. His own vow of never being controlled again not nearly as big of a deal since he was supposed with friends. But that submission would have lost him Alec, and later Valentina. Alec could have sided with the winning side.
And then there is the whole Nox’s family being kidnapped. If Alex wasn’t there to become Chevalier to Ant, Ant would have been too weak to get them out of trouble and Nox would have had to go in and save them, which means that there would have been torture and pain for his family instead of a quick return home.
The fourth book might have played out more simply. There would be no party in the Hamptons. There would be no alpha for a brother, which is key to when the Venatori come to the Night Life building in the end. But even before that, Griffin wouldn’t have been there to save Nox’s life several times. There might have been other bodyguards, but you don’t know the events would have played out for certain.
Nox would not have a connection to Poet – to find out he’s Prometheus and the second Ascendant. And they wouldn’t have a lead to go on when the Venatori attack at the end of the Power of Succession.
But having all these negative things, there is one fact that still remains, Nox and Alex are soul mates and they, by theory, should be drawn to each other. And Alex knows this and fights it, but he would eventually have to give in. But maybe it’s not until Nox gets rid of that dumb ass nightmare.
So how does that happen when all the vampire Dream Walkers are all pretty evil folks which is why the Venatori hunt Dream Walkers to begin with. So who can help find the nightmare, and eventually kill the demon? Probably Ant’s dad and or grandfather, they aren’t very proficient in Dream walking but I bet they’d know a nightmare when they saw one sitting on Nox’s chest one night. They’d know how to kill it and keep it from attaching itself to Nox. And with the nightmare gone, Nox and Alex could start soul mate dreaming again – falling in love – again. And Alex would come back into his life. And they’d live happily ever after. And this is where Nox yells “not!” because he knows it won’t last long.