Cortosis droids

Cortosis droids

The Cortosis Battle Droid is an improved version of the Super Battle Droid, armored with its namesake, a rare mineral only found on the planet Dxun. Being difficult for Jedi to destroy (Cortosis shorts out lightsabers), they were rushed into mass production during the Clone Wars. It fell to Anakin to destroy the factory that produced them, and during this mission, he discovered a critical weakness in their design; a small gap that ran vertically in their torso armor. After his success, no more Cortosis Battle Droids were produced.