Troops belonging to the Republic Defense Coalition were troopers operating under the banner of the Galactic Republic's Defense Coalition during the age of the High Republic Era. They accompanied Jedi investigator Emerick Caphtor on his mission to the Kharvashark Ruins located on Vrant Tarnum, to investigate the circumstances surrounding the death of Loden Greatstorm.
During the High Republic Era, the Republic was served by the troops of the Republic Defense Coalition, who could be deployed by the Jedi Order when operating under the direction of a Jedi. Following the attack on Valo, Emerick Caphtor, a Jedi investigator, was tasked with investigating the circumstances of Jedi Master Loden Greatstorm's mysterious death on Grizal, caused by the Great Leveler. After beginning his investigation, Caphtor led a contingent of Republic troopers to Vrant Tarnum, following the suggestion of Council member Stellan Gios, whose Padawan, Vernestra Rwoh, had visited the Kharvashark Ruins there not long before the Valo attack. The troopers prepared, and with Caphtor, set out for Vrant Tarnum. Upon arrival at the ruins, the troopers engaged with Nihil forces, eventually capturing at least two of them, while Caphtor moved forward to investigate the ruins more closely.
Later in the investigation, a number of Galactic Republic troopers accompanied Caphtor and private investigator Sian Holt as they confronted a group of Nihil transports and Stormships. Piloting Z-28 Skywings, the troopers kept the Nihil occupied, giving Caphtor and Holt the opportunity to board the main Nihil transport.
During the destruction of a Travyx Prime city, one trooper was serving as a pilot on the Pacifier-class sector patrol cruiser Galliance. In the battle at Ballum, Republic troopers collaborated with Jedi Santar and Keeve Trennis; the release of a Nameless hindered the Jedi's efforts. As one trooper contacted Commander Velko Jahen to report the Nameless's presence, the creature ambushed the Republic troopers.
The comic miniseries Star Wars: The High Republic: Trail of Shadows featured the first appearance of Galactic Republic troopers in its first issue. Daniel José Older wrote the miniseries, David Wachter provided the illustrations, and Marvel Comics published it on October 13, 2021.