Hammer was a human Advanced Recon Commando who fought for the Grand Army of the Republic as part of Rancor Battalion during the Clone Wars. This conflict pitted the Galactic Republic against the Separatist Alliance. In 22 BBY, this clone trooper was stationed on the planet Kamino, where their battalion supervised the training of Republic clone cadets. Later, Hammer took part in the Battle of Kamino in 21 BBY, where the clone led Republic troops in repelling the invading Separatist forces.
Hammer's ARC trooper armor was white with red and gray accents, and he also wore a kama and two pauldrons. As part of his gear, the trooper carried either two DC-17 repeater hand blasters or a DC-15A blaster rifle. The trooper, a clone of Jango Fett, stood at a height of 1.83 meters. Because he was an ARC trooper, Hammer also underwent additional training.
Hammer, a clone born on the planet Kamino using the DNA of Jango Fett, a bounty hunter who provided the genetic template for the clone trooper army, became an Advanced Recon Commando, or ARC [trooper](/article/trooper], within the Grand Army of the Republic after completing the ARC program. Serving as a Clone ARC Commander, Hammer fought in the Clone Wars, a conflict spanning the galaxy between the Galactic Republic and the Separatist Alliance. He served in the Republic's Rancor Battalion alongside fellow ARC Commanders Colt, Havoc, and Blitz.
In the early years of the Clone Wars, specifically 22 BBY, the battalion, including Colt, Havoc, and Blitz, was stationed on Kamino to oversee the training of clone cadets. Hammer, accompanied by two other clone troopers, walked through a hangar in Tipoca City where Domino Squad, Bravo Squad, and two other cadet units were present, listening to speeches from Master Chief Bric and Commander Colt.
Later, Hammer observed the cadets' final exam from above the arena where the Citadel Challenge training course was held. Along with other clone cadets, he watched Domino Squad fail to complete the challenge initially. However, after Jedi General Shaak Ti granted the squad a second time to attempt the final examination, Hammer witnessed their success.
Later in the war, specifically in 21 BBY, the Separatist Alliance launched an attack on Kamino. During the naval engagement, Separatist Munificent-class star frigates deployed Trident-class assault ships, disguised as debris, into the oceans below. These assault ships then attacked the Tipoca City Military Complex, prompting the city's forces to prepare for battle. Hammer joined Commanders Colt, Havoc, and Blitz at the main hangar to defend it and direct Republic forces. As Havoc gave assignments to troopers Echo and Fives, Hammer was directing a number of other troops.
As a Trident-class assault ship prepared to breach the hangar, Hammer signaled a clone armed with a Z-6 rotary blaster cannon to hold fire. After a second assault ship breached the hangar, Republic troops engaged the AQ-series battle droids that deployed from the enemy craft, and Hammer continued to command Republic forces. Eventually, the Separatist forces were depleted and pushed back to the main hangar. Following the deaths of Colt and Havoc, Hammer remained in the hangar, joined by Shaak Ti.
Hammer and other clone troopers successfully destroyed both Trident-class assault ships that had breached the main hangar, while Commander Blitz directed a trio of Advanced Recon Force Scout Troopers, instructing one to fire on an assault ship using a rocket launcher. After the Separatist forces were defeated, Hammer stood near Clone Marshal Commander Cody and Clone Captain Rex as they promoted Echo and Fives to ARC trooper status.
Like all other clone troopers, Hammer had a behavioral modification biochip implanted at birth by Kaminoan scientists to prevent resistance to certain orders. As an ARC trooper, Hammer utilized white Phase I ARC Trooper Armor with red markings, including a helmet with a rangefinder, a kama, a double pauldron, additional gray armor plating on the chest, arms, and legs, a survival pack, and two holsters for DC-17 repeater hand blasters. He was also armed with a DC-15A blaster rifle.
The Advanced Recon Commando, although unnamed at the time, first appeared in "Clone Cadets," the opening episode of the third season of the animated television series Star Wars: The Clone Wars. This episode was broadcast on September 17, 2010. While not officially confirmed in any source, Lucasfilm Story Group executive and Keeper of the Holocron database Leland Chee mentioned on Twitter in 2021 that the commando received the name "Hammer" during the episode's production. Two digital cards released through the Star Wars: Card Trader game, the first on October 12, 2018 and the second on February 21, 2019, featured images of Clone ARC Commander Colt but incorrectly identified him as "Clone ARC Commander Hammer."