The regulation manuals provided to the clone troopers serving in the Republic Military contained guidelines on proper conduct, and these guides were often referred to as "reg manuals" by the clones themselves. These manuals, accessible via datapads, included instructions for units when their sergeant was not present. Echo, a rookie clone trooper, enjoyed studying these manuals, a habit he maintained at Rishi Station located on the Rishi Moon in the Outer Rim.
Intended to educate clone troopers within the Republic Military on correct behavior, regulation manuals were available to read on datapads. These manuals featured an entry detailing the proper course of action for a clone unit when their sergeant was unable to command. The clones abbreviated the manuals' full title, preferring the term "reg manuals" when discussing them.
During the Clone Wars, a conflict spanning the galaxy-wide between the Galactic Republic and the Confederacy of Independent Systems, Echo, a clone trooper stationed at the Rishi Station outpost on the Rishi Moon within the Outer Rim, demonstrated a strong commitment to protocol, the regulation manuals, and the orders he received. His nickname, Echo, stemmed from his tendency to repeat regulations and orders verbatim.
On one day in 22 BBY, Echo entered the station's command center absorbed in one of the manuals. Hevy, a fellow rookie and heavy weapons specialist, voiced his frustration with the lack of combat on the moon; Echo countered that he appreciated the station's tranquility, as it afforded him time to study the manuals. Hevy expressed confusion at this, arguing that their purpose was to fight against the Separatist Droid Army. Cutup, another rookie, jokingly suggested that Echo had spent too long in his growth chamber, which annoyed Echo, who then turned back to the manual until Clone Sergeant O'Niner intervened.
Shortly time later, the station suffered an attack from a squad of BX-series droid commandos, resulting in the deaths of numerous clones stationed there. Among the casualties was O'Niner, leading trooper Fives to question their next course of action. Echo began to recite the instructions from the regulation manuals, only to be interrupted when a Rishi eel killed Cutup.
The regulation manuals made their debut in "Rookies," the fifth episode of the first season of the animated television series Star Wars: The Clone Wars, which originally aired on October 24, 2008. The full name of the manuals was first confirmed in the episode guide for "Rookies" on StarWars.com. In a behind-the-scenes segment for the episode, Supervising Director Dave Filoni humorously described Echo's strict adherence to the regulations as making him a maintenance duty clone. The StarWars.com article revisiting "Rookies" portrayed Echo's rigid adherence to the rules as his rookie mistake, contrasting him with the eager-to-fight Hevy. The blog post suggested that Echo's nervous reactions to any deviation from the rules stemmed from his lack of understanding that they were intended as guidelines.