Brigid is a noblewoman of Grannvale's House Yngvi, a full-blooded descendant of the Crusader Ulir, the daughter of Lord Ring, the sister of Edain and Andorey, and the inheritor of the holy bow Yewfelle. She was separated from her family and adopted by the pirates of Orgahil as a young child, eventually rising to become their leader. During the Agustrian civil war she was reunited with Edain and joined her in Sigurd's army. (Source: Fire Emblem Wiki)