Cassandra Alexandra is a character in the Soul series of fighting games. Cassandra makes her debut in Soulcalibur II, and has returned in Soulcalibur III and Soulcalibur IV as a standard character for all three games. She has appeared in the recent PSP video game Soulcalibur: Broken Destiny. The younger sister of Soul Edge character Sophitia, Cassandra's main goal is to relieve her sister from the burden of the Soul Edge and the oracles of the blacksmith god Hephaestus.
Cassandra has been mentioned as early as Sophitia's Soul Edge profile, though her name was mistranslated as "Kathandra". She's also briefly mentioned on Sophitia's Soulcalibur profile as well, both witnessing Taki bringing her unconscious sister home, which is when Sophitia meets her future husband, Rothion.
What lies in her soul is Courage.
In Cassandra's Soulcalibur II profile, as stated earlier, she witnessed Taki bringing back an unconscious Sophitia and pulling a fragment of Soul Edge out of her sister's body. So when Sophitia left again for a second time, Cassandra knew that she had gone out to destroy Soul Edge. Then, four years after the events of Soulcalibur, Cassandra visits Sophitia's home, only to be greeted by the sight of Sophitia's two children fighting 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, sneaking out of her home, she took the task of destroying Soul Edge.
Cassandra returned in the fourth installment of the saga, Soulcalibur 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.