Rosella grew up on a small farmstead south of Galduria in southwest Varisia. The forth of five children, she took turns tending to the livestock, and lived the life of a typical rural farmgirl. That pastoral tranquility was shattered when a couple of giants attacked the nearest village, killing a dozen people and slaughtering some of the livestock. In the aftermath of the devastation, her family joined a group of locals training to repel future giant incursions. To fight such large creatures, they learned certain acrobatic maneuvers to hopefully get close enough without being smashed into a pulp first.
When she was 13, she experienced a vision in her family's garden. The goddess Iomedae appeared before her, telling her that she was chosen to protect her homeland against an ancient evil that would arise in the years to come. When the vision ended she was overcome with emotion, and wept because the goddess was so beautiful. She resolved to redouble her training; to fail to prepare would be an affront to the Inheritor.
After three more years of rigorous training, she finally convinced some of the local militia to take her to Galduria to speak with the commander there. He heard her out, but scoffed at her talk of a holy vision, and ignored her warnings.
Shortly thereafter, Saint Lymirin, a servant of Iomedae, visited her in another vision. Appearing as an eagle-headed winged humanoid, the former priestess instructed Rosella to journey to Sandpoint and ready the population to face the troubles to come. As there had been report of increasing giant activity in the region, she took this to mean that a giant attack was likely.
Rosella is currently on her way to Sandpoint, to warn people about the Giant threat and to mobilize them. She is convinced that some greater force is behind the giant's activities, and that it's her holy duty to stop it.