Unlike other Cases, Vivi is a product of Project W born in the secret lab beneath the Cathedral—she's a Case through and through. Project W was an attempt to build a perfect Case with the bearing of an angel so that Augustine Empire could be the savior to end this calamity. Vivi is that perfect Case, though it'd be more accurate to call her the perfect victim. As a side effect of artificially-induced genetic variations, her body collapses from time to time. She needs regular care and maintenance to keep her from death's door. But anyway, the Empire did get what they wanted: In the eyes of the public, Vivi is the sacrosanct holy maiden who is invincible in battle.