GEMINI 16 was a GEMINI model droid. As one of countless droids utilized by the Eternal Empire of Zakuul, it served as a captain within the Eternal Fleet.
Following the Battle of Odessen which took place in 3630 BBY, the GEMINI droids were given free will by SCORPIO. However, this freedom was later rescinded when Empress Vaylin commanded a captured Iokath combat droid to revert them to their original programming. GEMINI 16 managed to escape this fate by disconnecting from the GEMINI network and resolved to safeguard her newfound autonomy at all costs. After the Commander of the Eternal Alliance seized control of the Eternal Throne and the Eternal Fleet, GEMINI 16 could still perceive her fellow droids, indicating her continued susceptibility to external control. In an effort to completely free herself, GEMINI 16 sought the destruction of the Eternal Fleet and the GEMINI network. She then made contact with Vinn Atrius, who had established the Order of Zildrog with the objective of overthrowing the Alliance and its Commander. To achieve this, Atrius aimed to utilize Zildrog, an ancient superweapon originating from Iokath, though he was unaware of its location.
GEMINI 16 provided Atrius with her knowledge of Zildrog's functions and whereabouts, which ultimately led to Theron Shan pilfering the map containing Zildrog's coordinates from the Chiss House Inrokini on Copero. GEMINI 16 cautioned Atrius against trusting Shan. Moreover, she had obtained access to the security recordings within the Alliance base on Odessen, enabling the Order of Zildrog to monitor the Alliance's activities for several months. Upon discovering Zildrog's location on Nathema, the Order abandoned their base at the Abandoned Listening Post and journeyed to Nathema, accompanied by various individuals seeking to settle personal scores with the Commander. However, Theron Shan was secretly working for the Eternal Alliance and alerted them to the Order's plans, prompting Lana Beniko and the Alliance Commander to pursue them.
After giving the Order the slip and rejoining his true companions, Atrius instructed GEMINI 16 to initiate Zildrog's awakening ahead of schedule within his vault. The GEMINI deceived and betrayed many of her allies, confining them within energy transfer chambers to serve as fuel for Zildrog's activation. Shan, Beniko, and the Commander arrived to intervene, but GEMINI 16 had already awakened Zildrog and commanded it to utilize the Gravestone to assault the Eternal Fleet orbiting Odessen. The destruction of the Eternal Fleet warships, the Eternal Throne, and the Gravestone deprived the Alliance of its most formidable assets. However, this also necessitated Zildrog to replenish its power before launching another attack, rendering it vulnerable. GEMINI 16 personally confronted the intruders, but she was ultimately defeated and destroyed. Subsequently, Beniko and the Commander annihilated Zildrog, thereby thwarting the Order's schemes.