The proto-saber, known to the Mustafarians as the laser sword, was a type of ancient prototype lightsaber locked away in an Imperial base near Fortress Vader on Mustafar. In 1 BBY, members of the Rebel Alliance undertook a mission to Mustafar, and discovered the proto-saber.
The proto-saber functioned differently from the lightsabers used by the Jedi Order during the Clone Wars. Instead of emitting a plasma blade, the proto-saber featured two physical prongs, which rose up from a crossguard. When activated, energy would surge up the prongs and form into a blade between them.
The Rebel Alliance undertook a mission to the planet Mustafar in 1 BBY. Having gathered intel regarding a dangerous artifact on the planet, Captain Cassian Andor sent a group of agents to a secret Imperial base. There, they recovered their target and discovered that it was the proto-saber. Their pilot, Athex, began to scan the object in order to send its data to the Alliance. The sword, however, flew out of the agent's hands and into the grasp of Darth Vader, who appeared from the shadows and attacked the rebels. The other agents attempted to give Athex cover fire, but Vader pulled the pilot toward him and stabbed him with his lightsaber. Just before Vader could strike the rest of the rebel operatives down, the reprogrammed security droid K-2SO crashed a shuttle into the building, buying time for the agents to escape. Once in space, the agents transmitted the proto-saber's data to the Rebel Alliance.
The proto-saber first appeared in Star Wars: Secrets of the Empire, a hyper-reality experience created by The VOID and ILMxLAB that opened in Walt Disney World in Orlando, Florida on December 16th, 2017, Disneyland in Anaheim, California on January 5th, 2018, and a limited release in London which ran from December 16th, 2017 to March 10th, 2018.
It was first identified on January 31st, 2018 on The Star Wars Show by Star Wars: Secrets of the Empire writer David S. Goyer. During an interview, Goyer stated, "That object, that we're calling for now the proto-saber, the idea is sort of a prototype of lightsaber and it may find its way into other mediums in the Star Wars universe."
Although no connection was made in Secrets of the Empire, the 2020 reference book Star Wars: The Lightsaber Collection conflated the proto-saber with the lightsaber of the Black Bishop, a character from another Goyer VR project, Vader Immortal. Lucasfilm Story Group member Matt Martin later clarified on Twitter that the two sabers were different weapons, stating that the proto-saber likely belonged to the Bishop's wife, Lady Corvax.
- Star Wars: The Lightsaber Collection
- Star Wars: Timelines