- "The Matriarch was generated from [Myrrah's] stem cells and Sire DNA. She amplified Myrrah's ability to communicate with the Locust."
- —Dr. Niles Samson explaining the Matriarch to Cpl. Kait Diaz.
The Matriarch, or Subject UL-119-2, was the first successful hybrid created at Mount Kadar Laboratory, and was the original Berserker of the Locust Horde. She was created by Dr. Niles Samson and his team of scientists by combining the embryonic stem cells of Myrrah, a human genetically immune to Imulsion, and Sire DNA to create a race of hybrids that would be resistant to Rustlung and utilized as a strong, obedient military force to aid the Coalition of Ordered Governments Army in the Pendulum Wars. The Matriarch was the "mother" of the Locust Horde and reproduced the first generation of Drones. The Matriarch also established a psychomagnetic link between Myrrah and the Locust Horde, known as the Hivemind, and allowed Myrrah complete control over the Locust. Preserved in cryogenic suspension, she survived past the Locust War and connected Myrrah's daughter, Reyna Diaz, and granddaughter, Kait Diaz, to the Swarm - an evolved form of the Locust Horde that survived the Imulsion Countermeasure Weapon. While more Berserkers were created following the Matriarch, she is the only of her kind known to exist and was killed by Cpl. Kait Diaz in 42 A.E. in an attempt to sever her link to the Swarm.
- "UL-119-2 remains our most physically dominant and remarkable specimen, surviving longer than any hybrid developed with embryonic stem cells. I remain baffled as to why this is so. The bond she seemed to have developed with EV-184-9 continues to intrigue me. All at once, this mighty, matriarchal beast can be calmed into quiescence by no more than a glance! Dr. Torres has developed a containment module for UL-119-2. He believes that by suspending her in cryptochromic fluid, the psychomagnetic bond she and EV-194-9 appear to share could be amplified. I am skeptical but willing to entertain his flight of theoretical fancy."
- —Dr. Niles Samson on the Matriarch.
The Matriarch was created in the Mount Kadar Laboratory around the mid-Pendulum Wars using the embryonic stem cells of Myrrah, a female child born with a genetic immunity to Imulsion, and Sire DNA. The Sires were once human children of Imulsion miners suffering from Rustlung, a fatal respiratory condition caused by overexposure to Imulsion vapor and fumes. Dr. Niles Samson attempted to cure Rustlung by splicing the children with the DNA of indigenous creatures from the Hollow because of Imulsion residing in their habitat. The Sires were distempered and sterile, unable to reproduce results for Dr. Niles Samson.
His work went from curing Rustlung to forcing human evolution into stronger beings capable of following orders and ending the Pendulum Wars. He attempted to create a hybrid using the Sires, but resulted in deformed offspring that were not able to survive. It wasn't until Myrrah reached adolescence that Dr. Niles Samson used her embryonic stem cells with Sire DNA to create the Matriarch, designated UL-119-2, surviving longer than any other hybrids created with embryonic stem cells. The Matriarch was naturally myopic, but had heightened senses in hearing and smell. Her massive size and natural armor made her almost impervious, except for a large, vulnerable blister on her back. The Matriarch also had increased speed, strength, and agility.
The scientists were originally unable to control the Matriarch due to her volatile nature. However, it was discovered that the Matriarch had a psychomagnetic bond with Myrrah - as Myrrah was able to communicate with and command the Matriarch non-verbally. This Hivemind gave great interest to Dr. Samson and the scientists of the lab. Dr. Torres then developed a containment module to suspend the Matriarch in cryptochromic fluid, allowing Myrrah's mental abilities to be amplified when connected to a brain-computer interface.
With Sire DNA, the scientists bred the Matriarch to produce the first generation of Drones - thus creating the Locust Horde. The scientists then learned that the Locust shared the same link to the Hivemind that was controlled by Myrrah. This inspired Dr. Samson to continue research into creating an army of the Locust for the sake of implementing them into the Coalition of Ordered Governments Army as obedient, powerful soldiers. Myrrah continually interacted with the Matriarch to use the extent of her power to control the Locust Horde.
After Dr. Torres became disillusioned with the lab's work and fled, taking his and Myrrah's daughter, Reyna, with him, Samson lied and told Myrrah that Reyna had been killed. Instead of settling the matter, Myrrah was enraged and directed the Locust to rebel against the lab's staff and guards. Myrrah and the Locust broke free and traveled to Mount Kadar, where they eventually created the Locust Horde, while the remaining personnel variously succumbed to their wounds or were frozen solid by a cryogenic purge of the facility that Niles had initiated before he bled out. The Matriarch remained alive and preserved within its stasis tank, which was maintained by an AI construct of Samson's personality over the following decades.
In 42 A.E., Kait Diaz and Delmont Walker entered the lab in search of information about Kait's family and her connection to the Swarm. There, the Niles AI explained how the Locust were created, why Myrrah rebelled and hated humanity, and how Kait had developed the same telepathic ability as her grandmother. In order to sever that telepathic connection, Kait used the interface with the Matriarch, which was connected to the Swarm Hivemind. Inside the Hivemind, Kait encountered the Matriarch who grabbed her and brought Kait to her mother. Kait inadvertently awakened her mother, now the Swarm Queen before Del severed the link. The Niles AI betrayed Kait and Del and turned the lab's defenses against them, and the Matriarch was freed in the process.
The Matriarch rampaged through the facility, observed by Kait and Del who were able to avoid detection for the most part. Near the exit, the Matriarch burst into a frozen cavern and destroyed the AI, killing Niles once and for all. Kait and Del attacked the Matriarch with old weapons left over from the Mount Kadar Laboratory Uprising, discovering that by dropping it into freezing water, they could freeze the Matriarch long enough to mount short attacks on its own weak spot. During the battle, Reyna telepathically attacked her daughter, distorting her vision and making it harder for her to kill the creature, particularly as the Matriarch neared death. Kait realized that the Matriarch served as her link to the Hivemind and that by killing it, she would finally be able to sever that link. Despite Reyna distorting her vision completely, Kait and Del managed to kill the Matriarch and sever Kait's link to the Hivemind.
When First Minister Mina Jinn later suggested reconnecting Kait to the Hivemind in order to locate the Swarm's central Hive, Kait told her that they'd killed the creature that served as her link to the Hivemind and sarcastically told the First Minster that "you're welcome, by the way" for having done that.
- Gears 5 (First appearance)