A member of the Gillette Corps, and an Assassin who utilizes needles as weapons. She serves as the Corps' infiltrator, alongside Zita. She greatly adores Albéric but never finds the time to properly confess her feelings to him.
Upon hearing that Albéric was caught in the magic blast caused by the Floating Fortress Soara, Viivi undergoes a sudden transformation; her hair turns white, and her eyes purple. Later, she is told that she was transforming into "Chaika," but that her transformation was only half complete thanks to her friends' interference; however, she is also told that "half is enough," provided she fulfills her role as a Chaika and gathers the Emperor's remains.