It seems we finally have the canon version of how Luke Skywalker acquired his green kyber crystal.
Charles Soule’s current Star Wars comic run is telling the story of the rebellion in-between The Empire Strikes Back and Return of the Jedi, and obviously Luke’s journey is a major part of that. His confidence in the Force and in himself was shattered after the happenings on Cloud City, and the run has shown Luke slowly growing beyond it. But Luke also lost his lightsaber in the duel against Darth Vader, and he first went back to Cloud City looking for it – without success. He then came into possession of a yellow lightsaber once used by a Jedi Temple Guard, but after using it for a while the crystal was damaged during a mission.
After this Luke decided it was time for him to explore making his own lightsaber, a journey that took him to Christophsis (the site of a major battle his father, Anakin, and Obi-Wan Kenobi were involved in during the Clone Wars). With enough kyber to be interesting but not enough to draw the Empire’s full attention, the planet was a promising location for Luke. There he met Cuata, an expert in kyber crystals who had been roped into Imperial service to work on the Death Star but who later fled.
Cuata taught Luke about kyber crystals, explaining that the crystals ideally bond with their wielder through the Force. That’s why Luke’s yellow saber wasn’t working, and even though his father’s blue saber was closer, it still wasn’t his. So Cuata offered Luke a deal: he first wanted him to bleed a red kyber crystal. Luke tried, seeing a vision of the dark side through the Force that involved his father (and connects perfectly to Charles Soule’s previous Darth Vader run), but was unsuccessful. In exchange, Cuata gave Luke an unbonded crystal. Luke connected with it through the Force and spoke with Yoda in what, unbeknownst to Luke, wasn’t a vision but reality. The crystal turned green, and Luke left with both the green and red crystals.

So we have not yet seen Luke actually construct the green lightsaber, which in the original deleted scene for Return of the Jedi happened on Tatooine right before the events of the film. Whether that will remain the canon explanation or not is yet to be seen, but it certainly appears that Luke now has his green crystal. And it also hints at how Luke will be far more powerful and proficient with this new lightsaber, because this crystal bonded directly with him rather than another person. As a huge fan of Luke’s green lightsaber (it’s my favorite in Star Wars), that’s a cool detail to expand upon.
We’ll surely continue to see Luke’s journey with these crystals, and it’s especially interesting that he took both crystals with him – not just the green one, but the red one. This might lead to further study and exploration into lightsabers, kyber crystals, and the Force, which I’d certainly be all for. But right now, it feels like we just witnessed an important moment unfold in this issue, which was one of my favorites in this current Star Wars run.