Cortosis ore was a very rare, brittle, fibrous material whose conductive properties caused lightsabers to temporarily short out upon contact, although the wielder could solve this problem by turning the blade back on after a few seconds. This effect made cortosis a useful material for anti-lightsaber melee weapons, though with repeated strikes, a lightsaber could still cut through it. Cortosis, due to its heat and energy resistant properties, was also resistant to blaster fire.
In the Hellcat Squadran Universe, Cortosis has seen increased usage, mostly by Coalition factions.
Some Hellcat Squadran Special Operations Armor is lined with Cortosis, to minimize the threat Sith would be to them.
The Kingdom of Dalmasca uses Cortosis in their Judge Magisters' blades. Anastasia Renner, for example, was presented with a Cortosis blade, as part of the ceremony when she ascended to the full rank of Judge Magister.
'Armors' used by higher ranked Neledia Alliance military officials are lined with Cortosis, to maximize the protection they offer on the battlefield.