During the Clone Wars, General Grievous, Supreme Commander of the Droid Armies of the Confederacy of Independent Systems, flew a customized Belbullab-22 heavy starfighter named the Soulless One, which had a hull made of impervium.
Behind the scenes
Impervium was first mentioned in the Star Wars Legends article Soldiers of the Empire! in 1978. Its first known canonical appearance was in the mobile-game Star Wars: Galactic Defense after a 2015 update.
- Star Wars: Galactic Defense (First identified as impervium)
- Star Wars: Episode III Revenge of the Sith (First appearance)
- Star Wars: Starfighter Missions
- Star Wars: Build the Millennium Falcon 40 (Starship Fact File: Modified Belbullab-22 – Soulless One)
- Star Wars Helmet Collection 51 (Databank A-Z: Soulless One–Super Battle Droids)
- Star Wars: The Complete Visual Dictionary, New Edition
- Star Wars: X-Wing Second Edition – Servants of Strife Squadron Pack (Card: )