
BOSS, also known as RC-1138, and Delta-38, was a clone commando in the Grand Army of the Republic during the Clone Wars and Imperial commando of the Imperial Army. He was nicknamed Boss by his fellow clones, and was the sergeant of Delta Squad.

FIXER, also known as RC-1140, and Delta-40, was an elite clone commando in the Grand Army of the Republic during the Clone Wars. Although he hated the use of nicknames, he was known as Fixer to the other commandos in his squad, because of his talent for fixing and slicing all things mechanical.
Unlike his fellow squad members had developed distinct personalities, Fixer was a gruff, by-the-book clone. Fixer was often the one urging his squad onwards during a mission.

SEV, also known as RC-1207 and Delta-07, was a clone commando and a sharpshooter in Delta squad during the Clone Wars. He was often referred to by his nickname of Sev, especially by his squad mates, and was well known for his sadistic sense of humor. Sev, alegedly, was given this name due to his love of severing an enemy's limb or body part. Sev aided the Republic in a number of missions, fighting on planets such as Geonosis, Coruscant, Skuumaa, Mygeeto, Dorumaa, and finally Kashyyyk, where he went missing in action. Sev completed many Black Operations for the Republic--covert missions typically involving activities that were highly secret due to questionable ethics and legality.

SCORCH, also known as RC-1262, or Delta 62, was a clone commando in the Grand Army of the Republic during the Clone Wars. Among the commandos of Delta Squad he was often referred to as Scorch, he was considered to be Delta Squad's wise guy, and was often chided by RC-1140 known as Fixer, the squads unofficial second in command.
However, most of Scorch's comments were aimed at Sev, and he was not afraid to talk back. Scorch was the squads demolitions expert, and loved annihilating anything that came in reach.
Info above as from Rebelscum.com
