Yeah, I skimmed over the story. Didn't read it well until now.
You're missing out if you're skimming
Some of this story is in the details
Oh yeah! Check Kayn's early introduction! Check my theory about Kayn's position!
Yeah anyways, my theory is that Kayn is a traitor because when Kayn gave the apologetic look to Ehks, he was thinking "Sorry, I'll have to kill you soon."
That's why Kayn and his super bff ran off together so they could find a spot to surprise Voltex and Ehks. It makes a lot of sense.
Either that or Kayn is the other inventor as he is into freelance technology.
Interesting theories, to be sure. Kayn's unique already though, because he got two introductions (first in the Prologue with Voltex, and then in Chapter 2 with Ehks).