Yale Karlsen served as a captain within the Imperial Navy. A male officer, he held command of the Ultimatum, an Imperial-class Star Destroyer, throughout the Galactic Empire's reign.
In the year 11 BBY, Karlsen was reassigned from his command for other duties. Consequently, Rae Sloane, a less experienced captain without a personal command due to a surplus of captains over Star Destroyers in the Navy, was temporarily placed in charge. While Sloane was the commander of the ship, they were tasked with transporting the industrialist Count Denetrius Vidian to the planet Gorse. This mission subsequently evolved into a conflict with local rebel forces.
During the unfolding conflict, Vidian proposed to leverage his influence to secure Sloane's permanent appointment, suggesting Karlsen could instead command a more advanced Star Destroyer in the future. Vidian later informed Sloane that he had arranged for Karlsen to receive an offer in the private sector. However, Vidian's treachery against the Empire was eventually exposed, and he was killed during the resolution of the Gorse conflict. Despite Vidian's promises proving empty, Sloane was permanently granted Karlsen's position as recognition for her role in Vidian's demise.
The character Yale Karlsen was initially referenced in the novel A New Dawn, authored by John Jackson Miller and published in 2014. His first name remained unrevealed until the short story "Bottleneck," also penned by John Jackson Miller. This story was included in the compilation The Rise of the Empire, released in 2015.