Could Rey's lightsaber colour hold the key to Star Wars Episode VIII?

The theory has its roots in the new Star Wars 'canon' explanation for how lightsabers can be different colours. According to Pablo Hidalgo, Lucasfilm's dedicated defender of Star Wars continuity, all lightsabers are originally colourless, with the 'kyber crystals' used to make them only gaining their shade depending on the personality of whoever collects the crystal and forges the blade.

Find a Jedi who’s big on meditation, and their blade will be green (we’re looking at you Qui-Gon Jinn). Get a Jedi who’s a tad more hands-on when fighting for the light side and their blade will be blue. And purple? That’s for somebody who’s between the light and dark. Oh, and red equals Sith. Obviously.

All of which begs the question: what colour will Rey's lightsaber be?

In Episode VII: The Force Awakens, she uses Luke Skywalker's lost blue lightsaber, but having met with Skywalker at the end of the film, perhaps part of her training in Episode VIII will involve constructing a weapon of her own?

If so, we may start to learn a lot more about Rey's true nature.

Will it be blue after fighting against Kylo Ren in Episode 7? Or will her blade turn a more morally ambiguous purple? According to the novelisation, Rey felt the dark side within her during the same duel.

Or, horror or horrors, what if Rey's lightsaber turns red? What does that mean for the balance of the Force? As the theory points out, there have been plenty of whispers about Rey's true allegiances, with some suggesting that she is closer to the dark side than we'd like to hope.

So far, so intriguing. However, does this crystal conspiracy go further? What if Kylo Ren’s true colour isn’t crimson?

Bear with us here. The theory goes that owing to the size of The First Order, Kylo must know where a fair few kyber crystals can be found. So why would he use a cracked crystal in his lightsaber, resulting in an unstable blade that needs those devilish side vents? Wouldn’t it be easier just to make a new one?

Well, perhaps red isn’t Ren's real colour. As we saw in The Force Awakens, he’s constantly pulled between the dark and the light side, so maybe his colour would be purple or green. And he could hardly rock up to Supreme Leader Snoke with a Jedi’s blade.

So, to cover up his leanings to the light, Kylo retrieved an old saber from an ancient Sith burial site. Sure, it’s a bit broken, but it could be enough to convince Snoke of Kylo's allegiances.

All this is pure conjecture at this stage of course, but it makes for an interesting possible avenue for Episode VIII to explore. Could Ren and Rey swap places? Are they each about to show their true colours?

Sounds like a theory gone too far? Then think about this: why would Disney all of a sudden make clear that the lightsaber colour originates from its maker? Answer, you cannot.