ASP-38 Droids, also known as Vader Droids, were Darth Vader's security droids at Bast Castle. Equipped with a repulsorlift and 2 dual blaster cannons, these droids were deadly to anyone who dared to infiltrate the Dark Lord's lair. After the former Sith Lord's redemption and death at the Battle of Endor, these droids continued to function.
Some time after the Declaration of the New Republic, former clone trooper X1 started to rebuild the Galactic Empire, with himself as its leader. In order to learn the secrets of the dark side, the self-proclaimed Sith Lord traveled to Vader's long lost sanctuary.
X1's brother X2, now a Jedi Knight, was sent to Vjun to stop his brother. By the time he arrived, X1 had already left. X2 encountered these droids and a garrison of stormtroopers. Both were no match for the Jedi and were all slain. After retrieving Falon Grey's lightsaber and X1's holocron, X2 escaped in a TIE Advanced x1, after his X-wing was destroyed by enemy fire.