The Second Army, alternatively known as the 2nd Sector Army or by the moniker Green Mantle Command, functioned as a Republic Reserve Sector Army during the era of the Clone Wars. This army, based on Nubia, was under the command of Senior Jedi General Ry-Gaul and was one of the two Sector Armies that comprised Systems Army Alpha, which itself was led by High Jedi General Mace Windu. While officially tasked with the defense of the Corellian Oversector, the 2nd Sector Army's forces participated in battles across the galaxy serving as reserve troops for other Sector Armies. Notably, the 327th Star Corps of the 2nd gained considerable fame under the leadership of Jedi General Aayla Secura.
Following Emperor Palpatine's declaration establishing the Galactic Empire, the clone troopers belonging to the 2nd Sector Army betrayed their Jedi commanders in accordance with Order 66. Subsequently, the 2nd was placed under the authority of Grand Moff Fliry Vorru.
During the Clone Wars, the 2nd Sector Army was one of the twenty Sector Armies that constituted the Grand Army of the Republic, with its base of operations situated on the planet of Nubia. Known as Green Mantle Command, the 2nd was paired with another Sector Army to form Systems Army Alpha, which was directed by High Jedi General Mace Windu. Senior Jedi General Ry-Gaul directly commanded the 2nd, which was intended to serve as a reserve force for other Sector Armies.
The 2nd Sector Army's principal mission was the protection of Sector 2 and the crucial hyperlane intersections located at Denon and Duro. Denon, a planet-wide city or ecumenopolis comparable to Coruscant, was positioned at the junction of the Corellian Run and the Hydian Way, while Duro served as one of the initial stops on the Corellian Trade Spine after it branched off from the Corellian Run at Corellia. Later in the war, the 2nd also established a blockade around the Neimoidian Purse Worlds.

Initially, the 2nd Sector Army, as a Sector Army, consisted of 147,456 clone troopers along with supplementary support personnel, organized into four corps. Among the four corps within the 2nd Sector Army, the 327th Star Corps, led by Jedi General Aayla Secura, stood out as one of the most actively engaged units of the GAR during the Clone Wars. Soldiers of the 327th were recognized by the yellow markings on their armor and were under the command of Marshal Commander CC-5052 (known as "Bly"). Talon Squad was one of the squads within the Corps, and it was part of the 2nd Platoon, Bacta Company, Hawkbat Battalion, 101st Regiment, and the 7th Legion of the Corps. K Company of Hawkbat Battalion was another unit that is known.
In 19 BBY, the 327th Star Corps took part in the Siege of Saleucami, a lengthy and intense five-month campaign occurring near the end of the Clone Wars. Shortly thereafter, Supreme Chancellor Palpatine proclaimed himself as Emperor and issued Order 66 to the Grand Army. The 2nd Sector Army then turned against their Jedi leadership, resulting in Marshal Commander Bly and his troops personally executing General Secura on Felucia. Ry-Gaul only avoided the same fate as his fellow Jedi due to being on a special assignment in the Outer Rim. With the rise of the Galactic Empire, the 2nd Sector Army was integrated into the Imperial Military and placed under the command of Fliry Vorru, who became the new Grand Moff of Sector 2, which was subsequently restructured into the Corellian Oversector.
- " Guide to the Grand Army of the Republic " — Star Wars Insider 84 (First mentioned)
- The Complete Star Wars Encyclopedia (as 2nd Second Army)
- Star Wars: The Official Starships & Vehicles Collection 55
- The Essential Guide to Warfare