HM-3 functioned as a Legal analyst droid within the Galactic Alliance Senate chambers throughout the Second Galactic Civil War. This droid, HM-3, assisted Jacen Solo in modifying a legislative procedure concerning legal amendments, facilitating the acquisition of additional resources for the GAG. However, this very modification was subsequently employed to remove Cal Omas from his position in 40 ABY. Jacen drew a comparison between HM-3 and C-3PO, noting their shared humanoid form and distinct personalities, although HM-3 exhibited a markedly professional demeanor.