Erica is a member of the 'Copper Black Cross' - one of the European magic organizations that inherited secret rites from the Knights Templar and is based in Milan, Italy. Their battle tactics and colors (Red and Black) has likened them to that of red devils. Holding the rank of Great Knight and the title of Diavolo Rosso (Dark Red Devil, name given to the premiere knight in the order which she earned through her efforts dealing with Verethragna), she is a magic swordsmen that through coincidence meets Godōu and assists him while he's in Sardinia, Italy. Although in the Light Novels it is noted that she declared to discover the identity, and if possible seal, of the Heretic God manifesting in Sardinia it just happened to coincidentally be the very same day as when Godou declared he was going to Italy. Using her weapon Cuore di Leone (Heart of Lion), an enchanted sword that she can summon to her hand, known as the King of Lions.