Rival is the main antagonist and final boss of Star Ocean: Blue Sphere.
Rival caused Ernest Raviede, Precis F. Neumann and Claude C. Kenny's ships to crash on the planet Edifice. She had lost control of herself and had been in the process of destroying the world. In an effort to stop herself she caused the ships to crash knowing the heroes would try to protect the planet.
- Main article: Rival (Boss)
At different stages of the final battle Rival assumes the form of Lenneth Valkyrie and even retains the technique Nibelung Valesti which can easily destroy the entire party if they are close enough together.