Maria is the princess of her dimension known as the Pegasus Knight. She tried to defeated the Sex Demon King Shadahl with her allies Eclair and Miina.
Princess Mariarosa (マリアローザ), the Pagasus Knight, is better known to everyone as simply Maria. She is one of the Magical Knights (魔術士, Majutsushi) with the water-ninja Eclair and mage Miina. For many years she was guarded by Eclair from the shadows. Their mutual feelings of admiration would eventually turn to sex between the two women.
When the Evil Sex Demon King Shadahl began abducting the women of the lady on mass and raping them into submission as part of his plan for world domination. Maria and the rest of her friends from the Magical Knights followed to track him down. They tries to drain him of all his semen and seal away his magic to kill him, but he was gaining the upper hand. Miina fell first, and Eclair passed on what energy she had left to give Maria the upper hand. Once Miina came to, she stole some of Shadahl life force and used it to revive Eclair to full strength.
Their victory seemed ensured of finally killing off Shadahl by draining out every last drop of his wicked semen, but he was saved by his bird-familiar, Sara. She cast his soul away to be reincarnated. Not wanting to see Shadahl revived, Maria followed Sara's trail alone right to her master in the dimension of Earth.
Her first appearance was in Power Play! Volume 1 CH. 0 "Power Play #0".