This article contains spoilers for Star Wars: Doctor Aphra #25!The lightsaber's greatest weakness has officially returned to Star Wars lore. A Jedi's lightsaber is not just their greatest weapon; it is also a meditative tool, and a Jedi bonds with the kyber crystal contained within it. Every lightsaber carries an echo of the Jedi who wielded it - a sense of their presence - which is why the Jedi of the High Republic Era venerated the lightsabers of fallen Jedi. It is why the lightsaber of Anakin Skywalker became so important in the sequel trilogy.
But lightsabers are not without their weaknesses. There are certain types of radiation that can disrupt a lightsaber's circuits, preventing the blade channeling the power of the kyber crystal contained within. Fortunately, this particular weakness is little-known and difficult to duplicate. What's more, the Jedi's greatest enemies - the Sith - would never choose to take advantage of recainium radiation, because this energy would disrupt their own lightsabers too. But Star Wars comics have just reintroduced the lightsaber's greatest weakness, one that dates back to the old Expanded Universe.
Star Wars: Doctor Aphra #25, by Alyssa Wong and Minkyu Jung, reveals the secret of an ancient weapon known as the Sith Killer. This was fashioned millennia ago by a cult known as the Ascendant, who wanted to replicate Sith abilities using technology. Hunted by the Sith, they constructed a blade out of a rare ore called cortosis - a fibrous material capable of absorbing energy. The Ascendant planned the Sith Killer to be used in a blade-to-blade fight, knowing a lightsaber that struck it would lose power for a period of time. Unfortunately, the original Sith Killer was of limited use; cortosis is too brittle, and the blade tended to break.
Cortosis Ore Creates the Anti-Lightsaber
The Ascendant cult wanted to design a weapon to be used against the Sith, producing a final version of the Sith Killer that's just been unearthed by Doctor Aphra during the original trilogy era. However, the old Star Wars Expanded Universe reveals other ways for it to be used - those aware of cortosis' effect on lightsabers often lined their structures with cortosis as a way of ensuring Jedi and Sith could not break into rooms. These could then be backed up by defensive weapons and traps, with Force-sensitives understandably taken aback when their lightsabers failed them.
It's also easy to imagine other ways cortosis ore could be used. Had the Separatists known about cortosis ore, they could have easily coated their battle droids with cortosis. That would certainly have made their battle droids even more formidable, because they'd have effectively been immune to lightsabers - and that surprise would have given the droids an opportunity to cut the Jedi down with ease. The Jedi can consider themselves fortune this particular Star Wars secret was not common knowledge, however with the Sith Killer in the hands of a rogue like Aphra, it's clear there's now at least one lightsaber-beating weapon loose in the galaxy.
Star Wars: Doctor Aphra #25 is available now from Marvel Comics!