The Impregnable served as a stronghold on the planet of Amaltanna. During the Battle of Amaltanna, a conflict within the larger Clone Wars, it was utilized by Baron Edi Wedd of the Confederacy of Independent Systems as his base. Jedi Knight Bultar Swan, the battle's only survivor, infiltrated this fortress in pursuit of Wedd. After failing to gain entry to his command chamber, she employed her lightsaber to cause a short circuit in the door mechanism, effectively trapping Wedd within his own command center.
Edi Wedd inside of the Impregnable
