Fastbreeders, commonly referred to as Hex droids or simply hexes, represented a specific combat droid design. These droids were conceived and manufactured by Lema Xandret, a Human female who sought refuge from the reconstituted Sith Empire. Her flight was prompted by her attempt to shield her daughter, Cinzia, from being taken by the Sith for training. Subsequently, on the isolated planet of Sebaddon, Xandret cloned her daughter, giving the clone the same name, Cinzia. She then tasked the hexes with the absolute protection of this clone. These droids were imbued with a fragment of Lema Xandret's essence, known as an amnioid, which granted them surprisingly lifelike attributes. Driven by an intense desire to safeguard Cinzia, the droids were prepared to take any action necessary, even killing Xandret, their own creator.
Eventually, their existence came to the attention of the outer galaxy. A hex droid nest was seized and offered for auction by the Hutt Tassaa Bareesh. A skirmish erupted when several attendees attempted to pilfer the nest. In response, several hex droids emerged from the nest, directly engaging in the conflict. They accomplished this by melting a path directly through the vault door.
The hexes possessed a silver hue and stood approximately 2 meters tall when upright. They featured six appendages, each capable of functioning as either a leg or an arm. Their bodies exhibited a hexagonal shape, appearing elongated when standing. Each appendage could simultaneously target a different opponent. These appendages discharged pulses of blue energy. The hexes could also manipulate two limbs to generate a temporary electro-mirror, capable of deflecting even a lightsaber. Their bodies were equipped with sensors that absorbed blaster bolts instead of reflecting them. These sensors dissipated the heat, but if the attacks were too rapid, the sensors were prone to explosion. Furthermore, the droids possessed the ability to cloak themselves.
The hexes demonstrated remarkable adaptability during combat (with at least one being deployed unfinished and building as it fought), swiftly gaining an advantage over the Sith, Jedi, and Mandalorian factions engaged in battle. The Hutts' security forces also joined the fray. Certain sections of the Hexes' exterior could deflect blaster fire. Even powerful blasts from a heavy blaster turret could be redirected, and the droids used these reflected blasts to damage the vault walls in an attempt to escape. However, their limbs were more vulnerable, and ultimately, the other factions united to subdue the few hex droids that had emerged from the nest. The Sith and Republic managed to trace the hexes back to Sebaddon, and both factions dispatched forces there independently. Upon their arrival, their fleets were ambushed by the hexes, which seized control of their ships and turned them against each other.
Consequently, the Republic and Empire formed a brief alliance for a mission to destroy the hexes, aiming to prevent them from conquering the galaxy. After all, complete domination of the galaxy would be the most effective way to ensure Cinzia's protection. During this mission, the original Cinzia—now a Sith apprentice known as Eldon Ax—accompanied by Jedi Grand Master Satele Shan, discovered the clone. The clone was being held within a Force–neutral bacta tank, alongside the amnioid.
When the amnioid turned against Cinzia, attempting to control her and prevent her from heeding Shan's reasoning, Ax destroyed the tank containing the clone to liberate her. However, Cinzia perished from the shock of being released from the tank and her inability to breathe air. Subsequently, Ax assumed control of the hex droids and directed them to eliminate her Master, Darth Chratis, before allowing the droids to self-destruct. With Cinzia's demise, they no longer had a purpose for existence.