The Cortess Family, one of Alderaan's noble houses, existed as far back as the era of the Cold War. By this point in history, it was already considered one of the most ancient of all Alderaanian houses. Notably, they had become a subordinate of House Thul, thereby becoming allies to the Sith Empire. During this period, Baron Peyar Cortess was at the helm, leading the family through a time marked by the constant menace of Killik incursions. During the time of the Cold War, Cipher Nine from Imperial Intelligence was sent to Alderaan with the mission to expose the terrorist organization led by the figure known as the Eagle. The Imperial Agent made contact with Vector Hyllus, a Joiner operative, which allowed them to infiltrate House Cortess, despite the initial hostility displayed by Baroness Chay Cortess. After successfully gaining an audience with the Baron, the Cipher Agent was able to uncover a crucial piece of information: Denri Ayl, a highly respected Alderaanian mediator, had connections to the terrorist group. This discovery was made possible by accessing library records belonging to House Alde. As events unfolded, it came to light that Baroness Cortess herself was also providing assistance to the terrorists. The Imperial Agent attempted to confront Chay Cortess, but she ordered her guards to deny the agent access. In response, Vector Hyllus summoned Killik reinforcements, who proceeded to damage the Cortess shield generator located in Glarus Valley. After fighting their way into House Cortess, the agent exposed the Baroness's treachery to her husband, Peyar Cortess. Later, during the Galactic War, their son, Pashon, sought out Nine, after the agent's identity was leaked by Hunter, seeking to avenge his family, but he was unsuccessful. Many years later, during the Galactic Civil War, one member of House Cortess joined the Rebellion against Palpatine's Galactic Empire: Gram Cortess distinguished himself as a skilled and dependable pilot within the Alliance Starfighter Corps.
The ultimate destiny of House Cortess hinges on the player's choices made during the Imperial Agent storyline. After revealing Chay Cortess's betrayal, Vector Hyllus arrives accompanied by Killiks, who declare their intention to transform House Cortess into a new hive, integrating it into the nest's territory. Baron Peyar Cortess implores the player to oppose the Killiks, emphasizing his cooperation with the Empire. Should the player side with the Killiks, House Cortess will be annihilated and ceded to the Killiks, with all its inhabitants – including those slain, such as Captain Perovius – being converted into Joiners. Conversely, if the player chooses to support Baron Cortess, the House will be spared. Regardless of the House's fate, Dugan Cortess survives.