Aldren Dayos was a Jedi Knight of the Old Republic, belonging to the Human species. In the year 3957 BBY, Dayos participated in a joint Jedi and Republic operation, spearheaded by Bastila Shan, with the objective of capturing Darth Revan while he was aboard his capital ship.
Aldren Dayos, a Human male with Force sensitivity, was brought into the Jedi Order and taught the ways of the Force. Having successfully completed the Trials of Knighthood, Aldren was promoted to the rank of Jedi Knight at the dawn of the Second Sith War. This devastating conflict was triggered when Jedi Knight Revan, the very same individual who had guided the Galactic Republic's forces to triumph in the Mandalorian Wars, established his own Sith Empire and proclaimed himself the Dark Lord of the Sith.
In the year 3957 BBY, the Republic devised a bold plan to strip the Sith of their influential and charismatic leader. By executing this plan, they hoped to bring the war to a swift conclusion by destabilizing the burgeoning Sith Empire and affording the Old Republic Military the necessary time to regroup its forces. Aldren Dayos was a member of a strike force deployed by the Jedi and Republic to the planet Sernpidal. Alongside fellow Knight Anyara, Lieutenant Kagen Brendel, Mara Davos, Samar, and Lieutenant Haden Vazzar, Dayos and the team aimed to acquire a code cylinder from the Sith Commander Doel Scherp. This cylinder contained the command codes essential for the sensor systems of Darth Revan's flagship. The agents discovered Scherp's location on the planet, confronted him, and successfully obtained the code cylinder. Ultimately, the agents managed to secure the cylinder during an attempt to capture Darth Revan.
Following the completion of the mission, Dayos, Anyara, Brendel, Davos, Samar, and Vazzar successfully boarded Darth Revan's flagship and fought their way to the Security Command center. During the ensuing fleet engagement, Aldren and his entire squad encountered Darth Voren, along with fifteen Sith troopers and a number of Sith Marauders, all under his command. Engaging them in combat, Aldren and his team managed to acquire the codes required to access the SecCom computer system. They utilized these codes to direct the Sith security teams to the port side of the vessel, enabling Bastila Shan and her strike team to capture Revan. However, moments later, Darth Malak, Revan's Sith apprentice, made the decision to betray Revan and ascend to the position of Dark Lord of the Sith. Seizing the opportunity to usurp his Master's title, Malak commanded his gunners to unleash fire upon the bridge of Revan's command ship in order to eliminate Revan and all the Jedi present. After transmitting the codes safely to the Republic fleet, Aldren and his team perished when the flagship was destroyed by Malak's fleet, while Bastila captured the critically injured Dark Lord and escaped the ship before its destruction.