Captain-Supervisor Grammel served as an officer within the Imperial Army, overseeing the Imperial mining activities conducted on the planet Circarpous V.
Grammel developed a reputation for being both sadistic and ruthless, known for his frequent torturing of prisoners, regardless of whether it was necessary.
Upon discovering the existence of the Kaiburr crystal, along with the presence of Luke Skywalker and [Leia Organa](/article/leia_organa_solo-legends], he relayed this information to Governor Bin Essada, who, in turn, informed Darth Vader.
However, the prisoners successfully escaped captivity with assistance from two Yuzzem named Hin and Kee, as well as a fellow Human named Halla. During the ensuing chaos, Grammel sustained injuries from an explosion, resulting in severe burns to a significant portion of his face, damage to his ear, and requiring the "re-forming" of his right arm. Upon Darth Vader's arrival, the Sith Lord expressed his disappointment with Grammel's failure to prevent their escape. Furthermore, Vader assumed command of Grammel's troops.
Grammel received orders to capture the leaders of the Rebel Alliance, a mission he was unable to accomplish. Despite—or perhaps because of—his pleas and justifications, Darth Vader executed Grammel due to his incompetence.