The Acolyte seems to be in the business of writing new lore for Star Wars, even if it breaks canon or makes certain choices in the original Saga a little dubious. The latest update from the show makes one of the most important metals in the universe potentially story-breaking, due to its various properties.
The latest episode of the show introduces audiences to Qimir, the menacing Sith-posing character, who wears a helmet and a gantlet made of Cortosis. Cortosis has a unique presence in Star Wars Legends, being a brittle metal that makes weird things happen to blaster fire and lightsabres, as depicted in the episode. However, the show has updated the metal, to have properties that most fictional metals strive for, possibly making it one of the strongest anti-Jedi/Sith materials of the Star Wars Universe.
The Acolyte depicts Cortosis as being strong
Cortosis, up until the current episode of The Acolyte, is depicted as a brittle metal, that is difficult to fashion into any sort of armor. However, the armor worn by Qimir in the show is depicted as being extremely strong, while retaining it’s properties to cause lightsabres to malfunction.
Given that there do exist Cortosis weaves in the Legends timeline (which functions as an alloy consisting of Cortosis and other metals, allowing them to be forged into weapons and armor), it seems that the show has decided to do away with that need, turning Cortosis into a powerhouse material of its own. While metals like Beskar can also withstand lightsabers and blaster fire, Cortosis takes it a level further, causing lightsabers to malfunction briefly upon contact.
This change to canon merits the existence of Cortosis in Mandalorian ranks
The Mandalorians have a long and storied history of fighting with the Jedi and the Sith on various occasions. Be it it the Mandalorian-Jedi Wars of old, or the more recent conflicts like Darth Maul’s invasion of Mandalore, the Mandalorians have been at odds with force wielders for quite some time.
While Beskar has proven to be quite the weapon against Lightsabers and blasters, Cortosis would have been metal that would have been of great importance to Mandalorians, during and after the war with the Jedi.
Cortosis would be an important material for the Mandalorians and would be something that is actively taught about in Jedi Temples. However, the utter absence of this material in the canon so far either points towards the complete extinction of the ore in the last days of the High Republic, or it is simply a secret material that has evaded master craftsmen like Mandalorians and the Force Sensitive Jedi and Sith.