Controlling people's bloodlines is the stuff of epic long-term insane 4-D chess planning. If you want to give your game a flavour of someone really getting their fingers into everyone's business for nefarious purposes, just hint at them controlling who breeds with who.
Commentary by memnarch (who has not seen the movie)
Aha, so it's most likely Nute behind it then. And it's also intriguing that the end game with Mara would possibly be a super Force user of some kind. Maybe Anakin's going to be on Nute's payroll or something? I still can't think of anything that Nute would want with another after Windu was discovered and killed. There's been a very distinctive lack of large groups of Force users in this movie to try and infiltrate. I wonder if this is just meant to be an explanation for Rey being better at things or if there’s something else that’ll show up later. The Lost Orb was never shown outside of Episode I, but it’s made for a very nice MacGuffin in the comic campaigns all the same.
And time to move on it seems. Or maybe it’s another instance of Luke attempting to ditch Rey and Chewie. It doesn’t look like they’re moving to follow him just yet anyway. As for where they’re going, maybe they’ll be going back to the submarine-wing. I can’t think of anything that could still be actually useful there in the movie, but comic-Luke could claim he left Obi-wan’s original recipe in there.
Luke: There’s one entity known for combining nefarious plans with cloning technology.
Chewbacca: Nute Gunray.
Luke: I can’t be sure, but it’s a good bet.
Rey: But my mother’s dead? So whatever plan he had failed.
Luke: I don’t think Mara Jade was the intended end game. He wanted a Force user to... mix with my bloodline.
Luke: That’s why Leia and Han kept you hidden. You’ve been keeping up the blue milk?
Rey: I had blue milk bread rolls four days ago.
Luke: Follow me.
Rey: Where are we going?
Luke: I’ve already told you too much. I’ve had years to practise being a Jedi Master. I really should be more cryptic.