Maria was a beautiful vampire who is the leader of her coven, and Jasper's creator. She is not a vegetarian, and mainly drinks human blood.
Maria was born somewhere in Mexico in the early 1800s. She was turned into a vampire by Antonio, leader of the Monterrey Coven. After spending her time with the coven, Maria decided to leave and make her own coven. Her maker refused to let her do that, but Maria disobeyed his command and traveled somewhere south to create her coven. She eventually turned her parents and her lover, Leon into vampires where they would try to form the coven. This was when they were confronted by another Mexican Coven when they were hunting. The coven battled her coven mates for all intent and purposes, leaving her defeated and alone. She joined rank with Lucy and Nettie to help her get vengeance.
While looking for humans to transform for her newborn army during the Civil War, Maria found Jasper Whitlock, a major in the Confederate army. Using the the idea pioneered by Benito, she used the army to fight for territory in the Southern vampire wars and trained her soldiers harder than anyone had bothered to do before.
After Jasper's transformation, she soon found him very useful in training, disciplining, and leading the other newborns. Using his supernatural talent to control emotions, he made the newborns cooperate with one another. With Jasper, Nettie and Lucy, Maria's army began working together better and their army began winning back several territories the territories she had previously lost as well as other Mexican territories belonging to other vampire clans. However, the southern vampires never gave up until the Volturi arrived. However, soon she became greedy and sought to extend her control further. Jasper, who she had placed as her second-in-command, was very close her, and thought of her as a god-like figure.
One night, Maria ordered Jasper to kill all of the newborns who had, in her eyes, lost all of their potential. It made Jasper sick and depressed to do this. She became aware of Jasper's depression and became paranoid he would turn on her. So she made plans with other newborns to plot against him, promising them Jasper's position. Jasper recognized this, and did the same with other newborns. But before either of them could execute each other, Peter, a vampire whom Jasper had let escape years with another newborn named Charlotte before, returned and took him to the North for a more peaceful life.
Maria decided to put an end to this constant cycle, and spared the remaining newborns that she had. She decided to remain somewhere north and stay away from the Southern vampire covens. Despite her efforts, it is revealed that several vampire covens were fighting against each other...leading to a Southern Vampire Civil War. It was a battle fought between vegetarian covens against the non-vegetarian covens (who are the ones that drink human blood). The few covens that stayed neutral throughout the war were able to put an end to this conflict, forcing the non-vegetarians to either stop or die while they left the vegetarians to live in peace. Maria was too fond about the war, but she soon realized that it was over, and she would never lead another army again.
Years later after hospitals were formed, Maria decided that she and her coven would steal blood bags from hospitals instead of killing and preying on humans. She sent her regards to Jasper, noting that she had changed, and she would always remember the things she's done. Maria and her coven found somewhere to live in New Mexico, and she would always visit her friends. She was proud that Jasper became a vegetarian, but she figured that she didn't want to, since she only craves human blood. Maria held hope that other non-vegetarians would do the same thing like he did, and would never prey on the innocent again.