Sonia was the lone daughter to a wealthy general, living her early childhood in luxury while her country suffered from poverty and warfare. After her father was murdered for political reasons and her mother went missing, she was dragged into her country's civil war. She was trained to be an assassin under one of her father's partners. Many years later, she learns that her boss had killed her parents and that her jobs were often innocent victims in her boss' way. After she fails to kill him, Sonia retreats to America as a hitman.
While in Sunshine City, she joins the "Black Dragon" sect as she learned the true identity of their leader, Johann. She gets into a troubled relationship with him and she eventually only stays with the sect for money. While she was out on a job, she spots Jimmy and falls in love with him after fighting him. She decides to tag along with him and settle the score with her boss in the tournament.
She is a cool-headed and confident woman who uses her sex appeal to get what she wants. Sonia knows of Jimmy's love for Marian and is determined to stay by his side regardless of his feelings for her.
- Energy Upper - Sonia can send her opponents flying with a pillar of gray energy.
She borrows some of her moves from Sambo, mainly from the combat division. Her knives are used as homing projectiles.
- Dragons Blues - Rage of the Dragons