As a child, she lived in a monastery peacefully with her older sisters Marla and Hestia, as they were abandoned by their father Jedah at a priory when they were young. Although they found their new home constricting, the three got along well and helped each other get by. However, at some point in time, Jedah offered Sonya's sisters as live sacrifices to Duma in exchange for his trust. Escaping such fate with her sisters’ help, Sonya decided upon revenge and waited on her chance.

Later on, Sonya serves as a subordinate of Grieth alongside Deen, who keeps her in check and vice versa. Although she is aware of Grieth's cruelty, and hates him, she stands in Celica’s path, preventing her from crossing the desert. If Celica defeats Deen, Sonya retreats into Grieth's Citadel. After Grieth's death, she joins Celica's army, revealing that she thought that Grieth would get his just rewards eventually.

Is more classy than Jesse, and ends her nights blacked out in a Walmart dumpster.