The fortress known as Andeddu's Keep was erected on the Deep Core planet of Prakith, serving as the personal bastion of Darth Andeddu, a Dark Lord of the Sith. Situated far from any established population centers, the Keep was utilized by Lord Andeddu as both a private repository for Sith knowledge and the site of his concealed tomb. Before his death, Darth Andeddu escaped the Sith homeworld of Korriban and sought refuge in his fortress, aiming to evade capture by those who sought his knowledge. He retreated into the Keep's most secluded chamber, entombing himself—and his accumulated wisdom—within a sarcophagus. For thousands of years after the Dark Lord's demise, adherents of Darth Andeddu, known as the Malevolence, remained within the fortress, immersing themselves in the dark side of the Force while awaiting his eventual return.
By the year 137 ABY, Andeddu's Keep had deteriorated significantly, yet the Malevolence still inhabited it. They were present when the Sith Lord Darth Wyyrlok III arrived, sent by his Master Darth Krayt in pursuit of Lord Andeddu's ancient insights. The Keep became the location of their destruction, as Wyyrlok murdered almost all of them before compelling Gerlun, the sole survivor of his onslaught, to guide him to Andeddu's hidden sanctuary.
The Keep of Darth Andeddu was a large fortress complex that was built into the side of a mountain range on the Deep Core planet of Prakith. It stood hundreds of kilometers away from the closest city where people lived. The entrance was marked by huge gates that were there to keep people from getting in. When people went inside, they found themselves in a big room. From this room, different paths went to different parts of the fortress.
The Keep was not only the main place where the Dark Lord of the Sith Darth Andeddu lived, but also the place where the people who followed his cult, called the Malevolence, stayed. These cult members were in charge of taking care of the place for a long time after Andeddu died, just like he told them to. Even though they didn't usually have visitors, sometimes people would come to the Keep. When that happened, the Malevolence cultists, who knew a lot about the dark side of the Force, would start to bother the people who came in. They would hide in dark places and make scary noises to try to make the visitors scared so they would leave.