Jossa was a human woman. Born on the island of Skadi, as a teenager she married the warrior Letholdus Stirling and gave birth to Erasmus. When Erasmus was only a baby, Letholdus was killed by the Exekians and Jossa and her child were taken as slaves. Jossa continued to raise Erasmus until he was about ten years old, when he was separated from her and taken to the copper mines. As an adult Erasmus searched for her, but could find no trace of her whereabouts.
Since she is the mother of Erasmus Stirling, in art she is treated with special adoration. Depicted as a radiant princess, she is usually shown clad in white and silver, with a halo-like crown and jewelry made to resemble chains, signifying her slavery.