Heist on Vader's Castle

After recruiting the Knights of Ren on Varnak, Lady Qi'ra instructed them to infiltrate into Darth Vader's vault at his fortress in order to recover a Screaming Key for her on behalf of the criminal syndicate Crimson Dawn. Qi'ra provided the knights with access codes and a map of the fortress, which made their leader, Ren, confident of their operation even though they lacked a plan.

The Knights of Ren took their starship, the Night Buzzard, and soon arrived on the Gahenn Plains on the planet Mustafar. The knights went towards the fortress from the south on their speeder bikes. Ren decided to use an old entrance to the Sith cave, which was left unguarded, in order to enter the Vader's castle undetected. While the entrance was covered behind flowing lava, the knights used the Force to get past the lava flow and enter the cave.

As they entered the cave, one of the knights, Marinda, quickly realized the location's strong connection to the dark side of the Force. Bazzra then noticed what appeared to be Darth Momin's helmet lying on the floor. After the mask, which seemed to still have the Sith Lord's severed head inside, activated in front of Bazzra, she blasted the artifact.

After entering the castle, the Knights walked past various bacta tanks until they encountered the attendant Vaneé, who called summoned several lava troopers when the knights attacked him. The knights managed to effectively kill and hold the troopers while Ren used his lightsaber to clear a path and find Vader's vault. Once Ren managed to enter the vault, he used the Force to hear the screams of the key and find it among all the other artifacts that were hidden there.

The Knights soon realized that most of the lava troopers left and saw how the Dark Lord of the Sith Darth Vader arrived at his castle. As Vader said that the knights were not invited, he quickly killed Fyodor with the Force. Ren told the rest of his knights to leave while he engaged in a duel with the Sith Lord. While the two crossed blades, Vader questioned Ren's worth and told him that he could still fall even further, which gave Ren the idea to jump out of the castle and control the impact of the fall with the Force, which made him land safely in the ground.

After successfully escaping from the castle on their speeder bikes, Marinda told Ren that they probably moved up on Darth Sidious's target list. At the same time, Vader was left at the wreckage of the battle on his fortress pondering of the thought of the Knights of Ren. Along with other events, the fact that the Knights had managed to break into Fortress Vader led Sidious to the conclusion that the Sith had a new enemy, with Vader and him learning it was in fact Crimson Dawn orchestrating affairs against them. Meanwhile, the Knights, joined by "the Archivist," traveled to the dark side hellscape with the Screaming Key on Qi'ra's orders to retrieve the Fermata Cage.