G-90, also known as Gee-Ninety, functioned as an assassin droid for the Jayosbrand within the Assassin's Guild during the Imperial Era. This droid possessed a distinct design, featuring a large, round body with its head extending upwards.
Gee-Ninety, or G-90, was contracted for the assassination_on_vincorba of a pontiff, who had formed an alliance with the Crimson Dawn syndicate. This assignment, alongside Chilla Zin and Loriach, served as a trial orchestrated by the Sith Lord Darth Vader as part of his mission to dismantle the criminal organization. Vader ultimately terminated Gee-Ninety's existence after the droid's failed attempt to release prisoners undergoing torture.
Following his demise at Vader's hand, Gee-Ninety was reconstructed by Jul Tambor, a fate shared by numerous other droids. He then joined Tambor's anti-Imperial organization. During the outreach mission to the planet Brentaal IV, Gee-Ninety aided Tambor but cautioned him that Sabé was loyal to Vader. Tambor confessed he already knew this, but hoped to sway her to their cause. After Tambor was discredited following a bombing of Kantiema, his attempts to liberate Skako Minor failed. Gee-Ninety journeyed to Skako Minor, where Sabé destroyed him after she had returned twelve Skakoan refugees to the world.