Many Star Wars movies have elaborated on the concept of lightsabers, bringing new and different takes on the blades and hilts with each subsequent release. But Kylo Ren's weapon is among the most unique versions in the canon.
The grossguard is the most notable visual difference to other lightsabers, though it serves a design function rather than being used in battle or simply because it looks cool. It actually comes from the item used to generate the lightsaber's blade - the Kyber crystal. The one in Kylo Ren's just so happens to be cracked.
Take a look below:
In the canon, Kyber crystals are inherently powered by the light side of the Force. In order for a Sith or dark side user to wield a saber, they must partake in a process called "bleeding." In Sith practices, it means killing a Jedi and taking the Kyber crystal from their own blade, but this isn't necessary to produce a red lightsaber blade.
The dark side user must bleed the crystal by overpowering it with dark side energy, which turns it red. It seems that Kylo Ren, either through his inexperience or his raw strength, caused his Kyber crystal to crack.
Though it still works, it's instability forced him to change the design of his hilt to create exhaust vents, or quillons, which create the crossguarded blade.
The Visual Dictionary also explains that Kylo's lightsaber is an ancient design dating back to the Great Scourge of Malachor, an event previously touched on in Star Wars lore. It was during this event that the Jedi had what could be considered their greatest victory over the Sith, killing many in their rankings.0comments
The event was first referred to in Star Wars Rebels and later in the Darth Maul comic. Hopefully we can glean more information from this epic battle in a future Star Wars story.
Star Wars: The Last Jedi is now playing in theaters everywhere.