Hex tech crystals are a combination of magic and advanced technology. But Jayce isn’t innately magical, he is using magic the same way Ezreal is using magic (after Ez lore update).
So will Demacians put him in jail or execute him?
Jayce is not a mage, he is an inventor that come across a magical item like the brackern crystal. Without it he cant do magic, thats the entire point of hextech is to make magic a commodity. Also why would he ever go to Demacia, that place has nothing of interest for Jayce.
They would likely take away the hammer and try to destroy it and after that they'd likely lock up Jayce for some time and interrogate him about it(to make sure that jayce himself isn't a mage).
If Jayce can convince them that the hammer is just a magical artifact,then they'd likely just punish him for bringing a magical artifact into demacia(though they likely wouldn't kill him),if they think that Jayce himself is magical,then they'd likely banish him or try to "cure" him from his magical abilities.
They don't just execute mages in demacia,the guy who was executed by Garen in the short story about Nocturne was executed because he murdered other demacians(though he did it under Nocturnes influence),not because they believed him to be magical.
I dont think that Hextech would work in Demacia due the stone that they have
Yes they would. As far as I know, Demacia doesn’t differentiate between the two. They abhor magic due to a calamity that happened because of the usage of magic not the mages in themselves. Remember the World Runes? Yeah those troublesome stones that anyone who wanted power could use be it a natural mage or not. In fact, I’ll argue that people who were not a natural mage had far less control over it and caused the greater troubles. In contrast with Ryze.
However, what Jayce could do is trick Demacians into thinking he is using advanced science.
By the way, just a part of a the crystal was enough to power the Glorious Evolution of Viktor and many people would find that movement questionable and dangerous. It’s not just a harmless thing that Demacia could slide if they knew how powerful it was.
First of all, mages don't just get executed in Demacia. They get relocated to villages on the border, basically exiled. Demacians don't hate magic, they are just very suspicious of it's destructive potential and don't want to risk having it in their borders. That's why I don't think it would matter if Jayce's hammer is magical or not. What matters is that is has a power source with enough energy to create a giant explosion should it malfunction. And Demacian border patrol definitely won't allow something like that in their country and deny Jayce entry.
