The main character. A very powerful witch that hates conflicts, because of this she interferes with any violence including battles, by summoning mystical creatures that are really big. Although the heavens take notice of Maria's actions and the Archangel (and Saint) Michael comes down making a decree that if Maria loses her virginity she will also lose her powers. Ezekiel, an angel dispatched by Michael, is left to keep an eye on Maria, making sure she doesn't tip the "scales".
It's shown in the anime that Maria was not accepted into villages before she reached the village where Martha lived during a plague. She'd received the villagers trust by giving them medicene to keep people from ever getting sick. She has built her home in the forest due to the villager's acceptance.
At the end, Maria has married with Joseph and Ezekiel will be reborn as Maria's daughter.
(Source: Junketsu no Maria Wikia)