Tosca Yayal-Ricci was a self-taught swordswoman and tinkerer with impressive skills and brutality in combat, which helped her quickly make a name for herself as a mercenary. In 1490, she met an aspiring dancer named Sofia Yayal, who she befriended and soon the couple became inseparable. Circa 1492, Sofia was killed during a dispute between a Templar Lord and a young boy.
Tosca took Sofia's last name and began to hunt and kill Templars in revenge. The Italian Brotherhood eventually tracked Tosca down and inducted her into the Assassins, redirecting her anger towards protecting the innocents. Using her newly acquired skills and her swordsmanship, she continued on her quest, becoming known as the wandering mercenary of Florence.