- "The planets are still aligned. There's still time!"
"Not for you. Not anymore."
"I can still finish this."
"You've had your last go. Your reign is over."
- —Rama Khan and Gamemnae[src]
Gamemnae, also known as Gemma Cooper, is an ancient and powerful alien entity called the "Goddess of Technology". She is one of the former leaders of the planet Jarhanpur; a sister planet to Krypton and Daxam, and a high-ranking member of Leviathan who, after the removal of Rama Khan from said position, became the organization's new leader, dubbed the "Guardian of Earth". Following the creation of Earth-Prime, she is also a mentor to Andrea Rojas and a board member of Obsidian North, whether she had this title on Earth-38 is unknown.
When Andrea Rojas and Rama Khan teleport to and fight at Leviathan's hideout, due to Khan being defeated by Supergirl, Gamemnae appears to break up the fight. She tells Khan that his reign is over and takes over the leadership of Leviathan as Khan tells her that this is not over.
During the Anti-Monitor Crisis, Gamemnae as well as everyone in the multiverse except for the seven Paragons, was killed in an antimatter wave by the Anti-Monitor on December 10, 2019, only to be restored a month later, after the Paragons and the Spectre created a new universe.
It's unknown exactly how much of her history was changed, however in the new multiverse, she goes by the legal name Gemma Cooper and was a college mentor and friend of Andrea Rojas. While looking over her work with Obsidian North's "Collective Dream" VR lenses she convinces Andrea to create an alternate reality for people to stay permanently who are unable to function in normal society. 
Gamemnae was present with Andrea Rojas when Lex returned from touring the world and advertising Obsidian Platinum globally. The leaders of Obsidian North were pleased with their alliance with Luthor Corp as Lex had also launched satellites that advanced the VR beyond National City.
Lex Luthor confronts Gemma Cooper and tells her that he knows that she is a member of the secret organization called Leviathan and that she is really Gamemnae, the goddess of technology; Lex wants to know what he can do to join. He further quips that he can help her to conquer the Earth without interference from Supergirl if she loans him her most trusted agent. Since Lex was so helpful with his worldwide advertising of Obsidian Platinum, Gamemnae chooses to entertain him but she must know if he can be trusted and what else he can do to support her cause. She orders a female Morae to do his bidding.
When Lex returns, Gamemnae is upset; her most trusted agent is captured by the Superfriends and Margot Morrison is dead by his hands; Lex explains that sacrifices had to be made for the greater game, revealing that the greater goal was the destruction of Supergirl as now the Superfriends will not stop Obsidian Platinum from advancing.
Worldwide unity festival
Gamemnae decided that Lex Luthor had earned a place with Leviathan and decided that he could see the headquarters, so the next morning, she ordered Rama Khan to disable the protective shields of the mothership. However, Rama Khan got higher orders from the Elder that no one was worth their safety and not to stop the radiation that hurt all but Jarhanpurians; thus, he left it active and when Gamenae and Lex arrived, Lex was paralyzed with pain. Gamemnae gave the human a lapel pin that made him immune and welcomed him to the organization. Since it was the day of the Worldwide Unity Festival, Gamemnae and Lex got assurance from Rama Khan that Supergirl would not interfere since he had enough Kryptonite to kill her; they watched as Rama Khan, Tezumak, and Sela loaded their rings with radiation.
At the very beginning of the festival, while Gamemnae was in an office of Obsidian North, the Elder had a telepathic meeting. The message was so jarring that Gamemnae revealed her true form onscreen where anyone could have seen; fortunately, only Lex entered the room, wondering why she was making this revelation. Gamemnae explained that Rama Khan was failing, even being temporarily disintegrated in a warehouse, and Supergirl was still alive to interfere. Lex suggested that another assassin should be used, especially while Supergirl was in Obsidian Platinum, leaving her physical body helpless.
Gamemnae went to Andrea Rojas and reminded her that they have known each other since Andrea was in college; Andrea was told to use her alter ego of Acrata to kill Supergirl. Andrea hesitated to follow orders, causing Gamemnae to threaten her father.
Later, Gamemnae was forced to use her powers to resist being teleported back to the mothership headquarters; her resistance caused her to shed once again her flesh-like disguise as Lex watched. He then fled the office. Meanwhile, Supergirl talked over two billion people into reclaiming their bodies and exiting virtual reality, spoiling Gamemnae's plans to have a limp, helpless world to conquer. Ultimately, with Leviathan captured and Supergirl successful through Andrea's failure, the goddess of technology screamed in frustration.
Powers and abilities
- Jarhanpurian physiology: Due to Gamemnae's Jarhanpurian physiology, she has superhuman physical attributes and she was gifted with the power of technokinesis.
- Technokinesis: Gamemnae can create, shape and manipulate technology and technological constructs, manifesting a form of electrical/telekinetic manipulation and a special form of morphing which allows her physical interaction with machines.
- Extended longevity: Gamemnae is nearly immortal having lived for millions of years, participating in ancient cataclysmic events.
- High-level intellect/Great business acumen/Master tactician/Leader: Gamemnae is a highly intelligent individual, an excellent tactician and leader.
- Master of deception: Gamemnae has maintained the disguise of "Gemma Cooper" for years, fooling many people into believing that she is human; however, she cannot maintain her facade when using her active powers.
- Staff of the Shadow World: After Rama Khan and Andrea Rojas are transported back to Leviathan's headquarters; Gamemnae grabs the staff from Rama Khan before he can strike Rojas.
Behind the scenes
- In DC Comics, Gamemnae was an Atlantean sorceress who was born 3,000 years ago. She forcibly became the ruler of Atlantis but she later learned that Aquaman and the Justice League from the 21st century would pose a threat to her rule sometime in the future. Therefore, she formed the League of Ancients in order to defeat the heroes.
- Gamemnae served as the main antagonist of Season 5 of Supergirl.