When she was born, her parents couldn't decide on a name for her, so they decided to give her all of the chosen names, resulting in her abnormally long name. She grew up with the idea of healing everyone in the world. Because of this, she was given the Thong of Compassion, intended to make her wish a reality. However, the thong corrupted her, making her originally passionate ideas twisted and murderous.
She used the power of her thong to take control over five gods, who had died before she existed. She then gathered an army of monks, who were scattered around the world in training camps for plans to retrieve the other thongs. Her ultimate goal was to heal only those she considered innocent, and kill those she percieved sinful. She would then send the healed men out into battle without their guns, which she would have given to her monk soldiers. With the power of all the thongs, she would have killed all life on Earth, because, in her own words, "No people. No war. Only peace."
DeathSpank was able to find her meditating inside the Catacombs of her own Sanctuary. Before he could fight her, he had to answer questions from her gods. If he got them wrong, DeathSpank would have to fight the god whose question was incorrectly answered. If he got them right, not only would he avoid fighting the gods, but they would strip Mary of some of her powers.