Elyse Aldomordish, also referred to as Elysse Nalerov in some sources, is a young woman who becomes the central figure in a conflict over a powerful military weapon. Her age is implied to be a teenager, similar to the series' protagonist, Tita. Elyse has a noticeably shy and bashful demeanor, particularly in moments of vulnerability or intimacy, which contrasts with the more assertive personalities around her. She is depicted as innocent and initially overwhelmed by the dangerous situation in which she finds herself.

The driving force behind Elyse's role in the story is her father, a scientist who was working on a secret military project. After he is gunned down by the forces of the antagonist, Lord Guizel, Elyse becomes the sole witness to his murder and, more critically, the key to activating the super-weapon her father helped create. Her father sabotaged the weapon and locked its controls using a code derived from Elyse's own DNA, specifically the last twelve digits of her sequence. This unique biological key makes her the primary target of Guizel's military forces, who pursue her relentlessly to unlock the device's world-threatening power.

Elyse's primary role in the narrative is that of a pursued fugitive who holds the fate of her planet's independence in her genetic code. Her escape from Guizel's men brings her into contact with Tita Mu Koshigaya, the captain of a pet shop hunting ship called the Cha-Cha Maru. Initially a stranger terrified and on the run, Elyse quickly becomes the catalyst for the story's central conflict as Tita decides to protect her. The relationship between Elyse and Tita is the most significant and focused-upon connection in the story. Tita saves Elyse seemingly on a whim and risks her ship, her crew, and her own life to keep her safe. A close and intimate bond forms between the two young women, with Elyse later expressing feelings for Tita that have been interpreted as akin to love at first sight. This relationship is the emotional core of the OVA, with their growing trust and affection for one another driving the plot forward.

Throughout the story, Elyse undergoes a transformation from a passive victim into a young woman with a determined sense of purpose. While initially needing to be protected and comforted, by the end of the conflict she resolves to return to her home colony to continue her father's scientific work, showing a newfound strength and commitment to the future. Her notable ability is not a physical or combative skill but the unique biological signature encoded in her DNA, which serves as the key to unlocking the Gravity Destruction Ray, a weapon capable of obliterating the floating colony. She has no special combat training and relies entirely on the protection offered by Tita and the crew of the Cha Cha Maru.