The defense fleet assembled by Moruth Doole was a fleet of mercenaries, established by Doole to safeguard his spice mining endeavors located on Kessel.
After the Galactic Empire was forced to withdraw from Kessel, Moruth Doole took command of the glitterstim mining operation situated there. He then prioritized the formation of a defensive fleet with the goal of shielding Kessel from the Empire, space pirates, and other criminal entities that might seek to seize control of the mines. He procured every available starfighter, regardless of its condition, and employed skilled mechanics hailing from the Corellian sector of Nar Shaddaa to repair them. Furthermore, he contracted mercenaries to pilot the vessels. Luke Skywalker later posited that this situation contributed to the New Republic's challenges in amassing a sufficient number of combat-ready ships during the Thrawn campaign.
By 11 ABY, the fleet had grown to encompass hundreds of ships, stationed on Kessel's Garrison Moon, with the larger capital ships orbiting the moon. Despite their aged and battle-worn appearances, the ships were meticulously maintained and upgraded to a high standard. During that year, Han Solo and Chewbacca journeyed to Kessel aboard the Millennium Falcon on a diplomatic mission for the New Republic. However, upon entering the system, they were ambushed by the fleet and crash-landed on Kessel's surface. The Falcon was subsequently recovered, repaired, and integrated into the fleet's ranks.
Subsequently, Han, Chewbacca, and Kyp Durron made their escape from Kessel and were attacked by the mercenary fleet, compelling them to navigate a course through the Maw Cluster. Lando Calrissian and Luke Skywalker arrived at Kessel shortly thereafter to investigate the fate of Han and Chewbacca. They seized control of the Falcon and launched into space. Determined to prevent their return to the New Republic, Doole ordered the entire Kessel fleet to pursue them, disregarding the tactical implications. However, as they pursued the Falcon towards the Maw Cluster, the Sun Crusher and three Imperial-class Star Destroyers under the command of Admiral Daala, which were also in pursuit, materialized. The Kessel mercenaries inadvertently collided with them, with some veering off to the sides in an attempt to escape, while others succumbed to panic and opened fire. Daala, suspecting a trap laid by the New Republic, ordered the Star Destroyers to retaliate, initiating a battle. The Kessel fleet managed to inflict minor damage on the Imperials, damaging the Basilisk and eliminating three TIE/LN starfighter squadrons. However, the mercenary fleet was hopelessly outmatched, and the majority of its ships were swiftly destroyed. The few surviving pilots abandoned the conflict by jumping into hyperspace, scattering in different directions.

- Endor [1]
- Gamma-class assault shuttles [1]
- Millennium Falcon [1] (Temporarily)
- 4 TIE/sa bombers [1]
- 3 Carrack-class light cruisers [1]
- CR90 corvettes [1]
- 2 Lancer-class frigates [1]
- 1 Strike-class medium cruiser [1]
- Refitted pleasure cruisers [1]
The creation of Doole's Defense Fleet is attributed to Kevin J. Anderson, and it played a role in his Star Wars: The Jedi Academy Trilogy, specifically appearing in Jedi Search and being mentioned in Dark Apprentice and Champions of the Force.
There is a slight discrepancy regarding the extent of the fleet's destruction during the Fourth Battle of Kessel. In Dark Apprentice, Commander Kratas states that two-thirds of the fleet was destroyed, whereas in Champions of the Force, Mara Jade asserts that ninety percent was annihilated.