Shura is a bonus character in Soulcalibur IV designed by guest artist Hiroya Oku.
Her weapons, named Raijin-Maru & Fujin-Maru, are twin katanas. She also has two wakizashi swords though she does not use them. Like all of the bonus characters, Shura's moveset is recycled from one of the main character's; she uses the same moveset as Cervantes. What lies within her soul is Hate.
The woman was simply a killer, one who had never tasted satisfaction. She eventually began to destroy evil spirits to keep things challenging. She slayed many of them until one day she became possessed by one. But even then, she did not stop killing. She continued her aggressive way of life, until the world was calling her "Shura", meaning "Bloodshed".
The spirit that had possessed her was in search of a powerful body so that it could return from the dead. As for the woman, she simply wanted someone worth killing. Together, they transformed from two strong warriors to a single, even stronger warrior.
The spirit still searches for a perfect body, with the woman still looking for someone strong enough to satisfy her.