Uldren served during the Reef Wars, discovering flaws in the House of Wolves’ communication networks.2 His Crows also helped to find errors within the Wolves’ flight trajectories, which led to a victory at Bamberga.3
Some time before the arrival of the Guardian at the Reef, Uldren located the Black Garden on Mars.4 After the Guardian acquired the eye of a Gate Lord, he gave them the location of the Meridian Bay Gate.5
Uldren served as an advisor to the Queen during the Hunt for Skolas.6
When Oryx arrived in the Solar System, the forces of the Reef assembled to confront him. Uldren led the assault on the Hive fleet. While the Queen’s Harbingers destroyed the majority of the fleet, they were ineffective against the Dreadnaught.
Oryx used the Dreadnaught’s weapon and most of the Reef’s forces were destroyed, causing Uldren to crash land on Mars. He used the Crow drones stationed there to make repairs to his ship and began looking for Mara.4 Some time later, Uldren began moving from planet to planet in order to attract the attention of the House of Kings; he was eventually captured and led to their Kell. 7 His ship remains on Mars.8
At some point, Uldren was involved in the operation of the Prison of Elders.9 Within the Telesto lore entry is a hidden message found by reading the first letter of every word: CROW UNTRUSTWORTHY DESIRES POWER. Given this message, some of the Reef leadership were suspicious of Uldren’s actions in the months after the Red War.