Lightsaber crystals are essential to the ancient Jedi and Sith weapons, so why is Rogue One: A Star Wars Story the only live-action Star Wars film to depict and address them? Since their introduction in 1977, Star Wars' lightsabers have been an iconic element of the franchise, but the films generally treat them as simply swords with laser-like blades. Non-movie material in both Canon and the original Star Wars timeline, the Expanded Universe (now called Legends), have explored the mystical, Force-connected, nature of lightsabers, particularly the crystals inside them. The crystals differ between Canon and Legends, and Canon's changes to the crystals’ lore (as well as the Death Star’s superweapon) necessitated their inclusion in the Canon spinoff film, Rogue One.
All lightsabers are powered by Force-connected crystals, making them intrinsically connected to their Jedi and Sith wielders. In Legends, the type and color of the crystals determine the blade color of the lightsaber. Jedi traditionally mined blue or green crystals, but occasionally obtained rarer purple or yellow crystals. Sith created crystals using the dark side, resulting in typically red crystals. Luke Skywalker and his New Jedi Order synthesized theirs as well, though they usually avoided Sith-affiliated red blades. In Canon, Kyber Crystals become a color upon bonding with a Force user, though dark side-users compel them to bond, “bleeding” the crystals and turning them red in the process.
Like lightsaber crystals in Legends, Canon’s Kyber Crystals can be found on many planets aside from Ilum. Rogue One establishes that the planet Jedha has an abundance of Kyber Crystals, which the Empire mines for use in the Death Star’s superweapon. In the film’s first act, Imperial and Partisan forces are seen fighting viciously over Kyber Crystals, and the protagonist Jyn Erso wears a Kyber pendant on her necklace. The crystal has no color, as it hasn’t bonded with a Force-user. Though mentioned often, no Jedi appear in Rogue One. Instead, the Guardians of the Whills (another Force-using religion) and the Sith are shown prominently. One Guardian, Chirrut Îmwe, joins the Rebellion and fights in the Battle of Scarif and proves to be as formidable as a Jedi Knight.
In Legends, Force-imbued crystals are only used for lightsabers, but in Canon, Kyber Crystals are sometimes used for other dangerous weapons. As shown in Star Wars Rebels, the Sith built Kyber-powered superweapons into some of their structures, such as the Sith Temple on Malachor. The Death Star continued this practice by using the crystals to power its super laser. In Legends, the Death Star was, as Vader put it, a “technological terror” with no connection to the Force or its dark side. While Rogue One changed this detail from Legends, it did allow Kyber Crystals to finally have their live-action debut and a brief explanation of their use in lightsabers.
Part of the appeal of spinoff material in Canon and Legends is that it explains the intricacies of technology, culture, and history within the two Star Wars continuities while allowing the mainstream films to keep their stories simple. Rather than delve into the mystical lore of lightsabers and their crystals, the films imply their Force connection by making lightsaber construction a vital rite of passage for Jedi, as shown in Return of the Jedi and Star Wars: The Rise of Skywalker. Rogue One: A Star Wars Story, despite the film not having Jedi appear, addressed lightsaber crystals because of their necessity to the Death Star’s main weapon.
