A recent episode of The Acolyte included perhaps the best anti-lightsaber weapon Star Wars has ever had in the form of cortosis, but it failed to explain why the Jedi Order didn't make use of it. The Acolyte episode 5 showed the Sith Lord using a helmet and gauntlet made out of a lightsaber-resistant material called cortosis, which he used to shut down the Jedi's lightsabers. Those cortosis weapons helped him massacre seven Jedi on Khofar, and proved just how invaluable the material was in fighting against lightsabers.

Despite cortosis ore's ability to shut down lightsabers, the Jedi never used it in any major way in any of the Star Wars movies or shows, even after the Sith revealed themselves in Star Wars: Episode I - The Phantom Menace. Part of the reason they didn't was because it was considered a dishonorable way to fight, much like the Stranger's use of a forbidden lightsaber combat form. There were a few more important reasons than that, though, which kept the Jedi from using cortosis in any meaningful way.

A big reason the Jedi didn't use cortosis is that it was a very rare material. There are currently only three planets in Star Wars canon that are known to have cortosis deposits, and one of them was the Stranger's base of operations. There simply wasn't enough cortosis in the galaxy for it to be used in any large-scale application, so it would only have been mined for specific purposes. Cortosis was so rare that most Jedi probably never encountered it in their entire lives, a fact that worked to the Stranger's advantage when he surprised them on Khofar.

The Sith Used Cortosis In Legends, Not The Jedi

Cortosis has always been a rare material, but it was much more prominent in Star Wars Legends than it is in canon. While Legends made use of cortosis more, it was mostly included as a weapon used by the Sith, not the Jedi. Cortosis became very important to the Sith after Darth Tenebrous and Darth Plagueis discovered a deposit of it on the planet Bal'demnic, a Legends planet that may have been the unknown planet in The Acolyte episode 6. The Sith used Bal'demnic up to the Clone Wars to create weapons to counter the Jedi, such as a battle droid with cortosis armor.

Of the times the Jedi encountered cortosis in Legends, it was mostly to counter a Sith plot. A Jedi task force was sent to Bal'demnic during the Clone Wars, and the planet was eventually protected against the Sith by a Republic fleet. That detail in particular might be a hint that the Jedi of Legends hid and guarded any planet known to have cortosis ore deposits. They understood the power cortosis had against Jedi, especially in Sith hands, so they likely tried to make sure no one could use cortosis, including the Jedi themselves.

The Jedi Aren't Used To Lightsaber Combat Anymore, Let Alone Cortosis

The main reason the Jedi didn't use cortosis in canon, however, was because they simply didn't have a reason to. The main advantage of cortosis is that it can temporarily disable lightsabers. The Jedi, however, hadn't fought any group who used lightsabers for the better part of 1,000 years. The Sith were the only real force the Jedi regularly had lightsaber duels with, but after the Jedi-Sith War, the Sith went into hiding. Since the Jedi thought the Sith were extinct, the Jedi stopped training for lightsaber duels because they believed there would never be a need for such skills.

Since they didn't think they would be fighting against lightsabers in any major way, the Jedi had no reason to use cortosis.

The Jedi did face a few people who had access to lightsabers in those thousand years. Marchion Ro, for example, stole Loden Greatstorm's lightsaber and used it to terrorize the galaxy. The Stranger, as well, used a lightsaber to devastating effect. These were both individuals, though, and the Jedi never ran into another group that widely used lightsabers. Since they didn't think they would be fighting against lightsabers in any major way, the Jedi had no reason to use cortosis. There was no reason to spend credits and resources on a weapon to disable lightsabers, and cortosis wasn't good for much else.

The Jedi's decision not to use cortosis may seem like a mistake in hindsight, but it likely wouldn't have helped them much in preventing Darth Sidious' rise or Order 66. Sidious preferred to use the Force as his weapon rather than a lightsaber, which cortosis had no power over. Cortosis also wouldn't have helped fight Darth Vader, since he would have been just as familiar with it as Anakin Skywalker as any Jedi. In that sense, cortosis is a uniquely Sith weapon, a fact The Acolyte displayed quite clearly during the Stranger's massacre of the Jedi.

New episodes of The Acolyte premiere on Tuesday nights on Disney+.