From Halopedia, the Halo wiki
During his service with the Covenant, Sluggish Drifter worked with Tul 'Imjanamee, a Sangheili engineering officer, several times. Upon the dawn of the Great Schism on November 2, 2552, Sluggish Drifter defected from the Covenant alongside Tul, G'torik 'Klemmee, Crun 'Brinsmee, and D'ero 'S'bud. Before the group departed High Charity, they intended to rescue Zo Resken, the Prophet of Clarity and a friend of G'torik. After the Sangheili killed the Jiralhanae tasked with executing Resken, they escaped into an energy conduit room. Sluggish Drifter unlocked a door for the group and locked out a group of Jiralhanae attempting to pursue them. The group made their way into a hangar bay and boarded a small maintenance vessel. The ship was piloted out of High Charity and into a small supply ship, Journey's Sustenance, captained by Shipmaster D'ero 'S'bud. Once they were secured in the supply ship's hangar, they escaped into slipstream space. Arriving in the Ussan system, Resken proposed for the group to search for the fabled Ussan colony, the Refuge, hidden within the system's asteroid belt.
Nearly a year later in 2553, the group was still searching for the Refuge and they were growing impatient. Sluggish Drifter asked if he could repair some of the small fragments of Forerunner metal that had been found in the asteroid belt, but Resken did not believe that even a Huragok would be able to repair them. However, D'ero discovered the Ussan colony shortly after. After making contact with the Ussans, the crew of Journey's Sustenance was allowed to came aboard into the colony. Arriving during a rebellion throughout the Refuge, Sluggish Drifter repaired the colony's disabled monitor, Enduring Bias. The crew of the supply ship and several Ussan patrollers traveled to Section Five of the Refuge to quell the rebellion. While Sluggish Drifter remained in the shuttle, the Sangheili and Enduring Bias wiped out or arrested all of the rebels in the section. Sluggish Drifter was brought to the section's malfunctioning protein synthesizer and he repaired it. Enduring Bias and the Huragok discovered that the broken synthesizer was inserting toxin into the protein it created, which was leading to Ussans becoming ill with Blood Sickness. While the Sangheili returned to Sanghelios or their respective homeworlds, Resken and Sluggish Drifter remained on the Refuge.
List of appearances