As the only child of scientist parents who investigated the 1908 mysterious touchdown site in Tunguskia, Russia, Sonya was born with the ability to generate "cold" fire in rings surrounding her wrists. It is believed that her parents were exposed to either radiation or an exotic gas that caused this mutation.
Raised by the Soviet military, who wished to exploit her abilities, Sonya was given the codename "Fireball" and raised as a true Socialist believer. As her uncle was killed during the German sneak attack in June, 1941, she vowed to do whatever it took to destroy the Nazi empire. As a token of co-operation between the Allied forces, Stalin ordered Fireball to join other heroes of the Allies in a group to be directed by the US government called the Young Allies.
After aiding another group of young mystery-men called the Young All-Stars, in June of 1942 against a group of Axis villains, Fireball and her partners were sent to England to aid in the upcoming attack on Fortress Europa. Nothing is known of her adventures after WWII.
Fireball was born with the ability to generate a high-heat plasma from around her wrists. After training with the Soviet military, she was able to fly and shoot fireballs from her hands. It is assumed she is also impervious to fire.