Marie Parfacy, also known by her implanted persona Soma Peries, is a super soldier from the Human Reform League's Super Human Research Institute. She was created as a designer baby, an orphaned test subject who lost her physical senses due to psychosomatic paralysis. At the institute, she befriended Allelujah Haptism, another test subject designated E-57, and they formed a deep bond. After Allelujah and other flawed subjects escaped and destroyed the facility, the scientists implanted a new personality called Soma Peries to overwrite Marie's memories and transform her into a perfect soldier. As Soma, she became a second lieutenant and pilot for the Human Reform League, operating the mobile suits MSJ-06II-SP Tieren Taozi and later the GNX-603T GN-X. During the first season, she was driven by a cold, mission-focused demeanor and held a special grudge against the pilot of the Gundam Kyrios, knowing he was a fellow enhanced human who had betrayed the super soldier project by destroying the research facility. She shared a mental connection with Allelujah due to their past, which sometimes caused her to go berserk in combat and required a special suit to suppress.

In the second season, Soma served under the A-LAWS, piloting an improved Ahead Smultron. Her encounters with Allelujah continued, and during a space battle, her true identity was uncovered when she abandoned the fight to rescue a wounded Sergei Smirnov, whom she regarded as a father figure for being the first to show her genuine care. Seeing her face, Allelujah recognized her as Marie, and the mental link between them triggered the recovery of her suppressed memories. Once she remembered her past, she chose to defect to Celestial Being, joining the crew of the Ptolemaios and piloting the GNR-101A GN Archer to support Allelujah in combat. As Marie, her personality shifted to being warmer and more emotional, reconnecting with her sense of compassion and her bond with Allelujah. She fought alongside Celestial Being against the A-LAWS and the Innovators until the conflict ended. After the war, she left military life and traveled the world with Allelujah, finally free from the conditioning that had defined her for so long. Her notable abilities include heightened reflexes and spatial awareness typical of a super soldier, a telepathic-like link with Allelujah, and exceptional piloting skills that allowed her to wield advanced mobile suits effectively. Her development from a brainwashed antagonist to a self-aware ally is central to her story, highlighting themes of identity and redemption.