Marie is a nurse on the Sabaody Archipelago. She was assisting in transporting a wounded man to a nearby hospital when they encountered Saint Charloss, a Tenryuubito. Saint Charloss refused to let Marie pass with the injured man and then kicked the severely wounded man to the ground, stating he would help him die. While Marie was kneeling in shock, Charloss noticed her and forcibly took her away to become his thirteenth wife against her will.
Her fiancé, who was also helping to transport the wounded man, stood up and pleaded with Charloss not to take Marie away. In response, Charloss shot him for "daring to stand in his presence." No one dared or could help her before they left.
Marie was eventually freed along with the other slaves of Charloss's family after Luffy's attack on the Tenryuubito.
Source: http://onepiece.wikia.com/wiki/Marie
