Cassandra's first appearance occurred in the third game of the saga, Soul Calibur II. Originally Cassandra replaced Sophitia entirely from the game's roster, taking her spot and similar movestyle. Despite this, Sophitia was later added to the list of characters on the home versions of Soul Calibur II, placing both sisters together as selectable characters. Cassandra carries two homages to past Namco games: One of her unlockable weapons is the Red Crystal Rod, which comes from Namco's Tower of Druaga and its sequels; and her third costume is modelled after Valkyrie, the heroine from Namco's Valkyrie no Densetsu.
As stated in Cassandra's profiles, four years after the events of Soul Calibur, Cassandra visits Sophitia's home, only to be greeted by the sight of Sophitia's two children, Patroklos and Pyrrha, fighting unusually angrily over a metal shard of Soul Edge that Sophitia's husband, Rothion, had found. Angered by her sister's panicked reaction, Cassandra ran to the Eurydice Shrine, screaming at Hephaestus for endangering her sister on behalf of his ego. After briefly passing out from exhaustion, she saw the metal fragment resonating with the holy Omega Sword, the sword her sister used on her past journey. Not wanting to see her sister take on another dangerous quest, especially now that she has a family, Cassandra stole the sacred sword and her own shield, sneaking out of her home to take on the task of destroying Soul Edge.
Cassandra returned in Soul Calibur III, as a starting character. She remained largely the same, with slight upgrades on her fighting style that sets her apart from Sophitia, and new costumes. Her profile follows her travels towards the east, where she finds a town covered in evil energy. Trying to help the inhabitants, much like Sophitia did in her last trip, Cassandra tracks the core of the evil in a castle atop the mountains. However, she discovers the sacred weapons she carried to have cracks all over. Forced to flee the city after being surrounded by the corrupted city-folks, she travels back to Greece to ask her brother-in-law, Rothion, to forge her new weapons. Once there, she was informed by Rothion that Sophitia left to destroy Soul Edge on her own. After receiving a new pair of weapons from Rothion, Cassandra sets out to search and join her sister in this quest.
- The Alexandra sisters are the only characters that do not give out their actual weights in their character profiles. They are listed as "refuses to tell" or "lost weight recently"