Maria is a new character introduced in Metal Slug Attack.
A newly appointed commander of the Ptolemaic Knights, Maria is quite timid and views the knights under her command as valuable allies. Due to her position, she wields the Sacred Armor and accompanying twin blades.
When heading into battle, she also wears the Sacred Armor's helmet, which appears to have sentience of its own. The helmet enjoys mentally torturing Maria by prodding at her weakness in battle. It offers to help in the worst situations, and when Maria surrenders herself to its will, she becomes crazed and fights for the thrill. Maria is well aware of the consequences of allowing the helmet to control her, though she continues training in the hopes that she will not have to rely on it in the future.
Though she doesn't need to take the mask if desired, since it soon became well known that the mask is behind her change in personality.
First appearing in "Dark Invitation", Maria and her squadron are sent to battle the Rebel Army. They take heavy casualties, and her helmet mocks her weakness, though it offers to assist her. Maria gives in to the helmet's temptation, and single-handedly drives the Rebel Army away. She manages to free herself from its control after the battle, aware of the consequences of relying on it.
In her next mission, she is paired with Sally to find the Red Goblin. She decides not to take her helmet for this mission. After apprehending a red-haired man, she realizes he is not the Red Goblin and wants to release him, but is stopped by Eri and Tarma. Maria fights Tarma, but soon spots another red-haired man with a woman, prompting her to abandon their fight and chase after the new pair, realizing they have some sort of link to the Red Goblin.
She is later deployed to capture the Elder Centipede, commenting on its mutation. A cultist tells her that it doesn't matter if it is still alive or dead, as long as it is brought to them. She then wonders where Sally has run off to, and searches for her. She manages to find and save her just in time, scolding her for running off. Sally tries to inform her that someone else is inside, but Maria states that she cannot rescue them as her sword cannot take any more attacks as the two escape.
While idling about with her knights, Maria's treasure possesses her again and she nearly kills her subordinates when Sally arrives and tricks her into getting strapped on a Black Hound. She is later rescued by Matilda, although she still retained her murderous intentions and chased after her into a crypt, encountering its guardian and killing it after a long battle. After trying to chase Cleopatra, she returns to Matilda and tries to kill her again, but Matilda had already anticipated her attack as she continues resuming her investigation.