Maria is a bio-weapon created by the same organization that produced Jo, designed as a counterpart with even more pronounced violent tendencies. She possesses a tattoo on the right side of her body, mirroring Jo’s tattoo on the left. Unlike Jo, who favors firearms, Maria relies primarily on bladed weapons such as swords and cutting wire, reflecting a more aggressive and close-quarters combat style. Her appearance is that of a teenage girl with gray hair and pink eyes.

Maria’s motivations are initially driven by a deep-seated desire to prove her superiority over Jo, whom she views as her rival. She abducts Meg in order to force a decisive rematch on an aircraft carrier, replicating the setting of their first unfinished confrontation. During this battle, Jo pushes Maria to her limits and defeats her in close combat. The fight restores Maria’s lost humanity, but she becomes uncertain of her purpose afterward. When RAPT forces attack, she makes a conscious choice to sacrifice herself, covering Jo and Meg’s escape and apparently perishing in the explosion. However, a preview set five years later in the OVA Burst Angel: Infinity shows Maria alive, suggesting she survived her sacrifice.

In the story, Maria functions as both an antagonist and a tragic figure. Her personality is characterized by a fierce, almost berserker-like aggression, stemming from her nature as a weapon created without a stable sense of self. Her development culminates in her regaining her humanity through defeat and selflessness, transitioning from a relentless pursuer of strength to someone who chooses to protect others. Her key relationship is with Jo, as they are mirror-image bio-weapons whose rivalry defines Maria’s arc. Her brief interaction with Meg serves as the catalyst for the final confrontation. Maria’s notable abilities are her enhanced physical capabilities, proficiency with bladed weapons, and the same bio-weapon physiology that grants her resilience and combat prowess.