The Borg never had an origin story on screen.
”The point is, I’m still not sure what the donut ships were there to do, and don’t any of you faggots tell me it was explained more in the novelization or some Star Wars book. What matters is the movies. I ain’t never read one them Star Wars books, or any books in general for that matter, and I ain’t about to start. Don’t talk about them stupid video games, or novels, comic books or any of that fucking crap. I seen enough of that shit.” – Harry S. Plinkett