The Emperor's plague storehouse, a clandestine research facility used by Emperor Palpatine during the Imperial era, was an unmapped asteroid situated in the Deep Core. Reaching the asteroid necessitated six separate hyperspace jumps and double the hours, due to the absence of a direct route.
This asteroid depot was a complex network of pressurized domes, tunnels, and sealed chambers that housed a variety of biological weapons. These weapons were capable of affecting a wide array of species, including the notorious Krytos virus and a virus specific to Humans known as the Emperor's Plague. The central hub of the depot, filled with rows of cylinders and tanks, contained the majority of these viruses. Around the perimeter of the plague storehouse were several docking bays. Within several sealed chambers lay the decaying remains of experimental subjects, primarily non-Humans or other adversaries of the Empire.
The plague storehouse once served as the headquarters for Imperial scientist Evir Derricote, the individual responsible for the creation of the Krytos virus. This bioengineered virus afflicted countless alien species following the Liberation of Coruscant in 7 ABY. Before his initial demise at the Battle of Endor in 4 ABY, Palpatine gave the order to store samples of the human-specific Emperor's Plague within the concealed weapons depot. Further, he directed the removal of the depot's coordinates from Imperial records to obscure its location. Only a select few high-ranking Imperials knew of the existence of this station and its depot.
In 24 ABY, an alien scavenger by the name of Fonterrat stumbled upon the Emperor's plague storehouse. Despite the Galactic Empire's defeat, the plague warehouse with its stockpile of lethal diseases, was still intact. Aware of Nolaa Tarkona's hatred for Humans, he offered to sell her a navicomputer module containing the plague storehouse's location. However, he refused to deal with her directly, suggesting she send a neutral party to meet him on Kuar.
During the negotiation, he also furnished her with a sample of the virus, which she used to seal his payment. The neutral party was revealed to be Bornan Thul, a wealthy Human merchant and shipping magnate who owned Bornaryn Trading. In exchange for the navicomputer module with the asteroid's coordinates, Bornan paid with a time-locked case filled with credits. Bornan was originally supposed to deliver it to Nolaa at a trade conference on Shumavar, but after discovering the contents of the plague warehouse, he went into hiding.
Nolaa also captured the last surviving member of the four Imperial Royal Guards who had spearheaded the Second Imperium's insurgency in 23 ABY, interrogating him to find the weapons depot's location so she could acquire its deadly collection of biological weapons. When he refused to cooperate, she had him killed using a sample of the Emperor's Plague.
Furious, Nolaa hired numerous bounty hunters to locate Thul and retrieve the navicomputer. Among them was Ailyn Vel, disguised as her father Boba Fett. In response, his son Raynar Thul—a Jedi trainee at the Jedi Praxeum on Yavin 4—along with his Jedi companions Jacen, Jaina Solo, Tenel Ka, the Wookiee Lowbacca, and his translator droid M-TD, began tracking him. They were later joined by Zekk. Following encounters with bounty hunters and visits to planets such as Mechis III and Ziost, they eventually caught up with Bornan and learned the reason for his hiding.
Subsequently, they successfully located the asteroid depot and planted explosives within it. However, a Diversity Alliance fleet under Nolaa's command arrived. During the resulting chaos, Bornan and several Alliance members, including Nolaa herself, were infected with deadly plagues released from shattered canisters and tanks. Bornan succumbed to a Human-specific virus and died.
Assistance for the Jedi arrived in the form of the New Republic Defense Fleet and the Bornaryn Trading Fleet, which triumphed over the Alliance fleet during the ensuing battle. After the Jedi had evacuated the asteroid depot, the combined New Republic/Bornaryn fleet obliterated the plague warehouse, destroying the plagues contained within. Nolaa Tarkona, however, escaped with the Wookiee Raabakyysh aboard her transport Rising Star, only to perish later on an unmapped asteroid in the Outer Rim.