Nina is The Main character and the person that swallowed a magic pearl. She now has Ichi and Zero living in her closet (transformed into a good-sized apartment), and the other teams chasing her constantly. She's falling for both Ichi and Zero, and can't seem to decide between the two. She's 12 years old and looks for a cute boy that can both protect her and love her.
Nina is a 7th grader girl with an aggressive character. She is targeted by many sorcerer examinees because she accidentally swallowed the crystal pearl which, in this case they need that pearl to pass their exam to become a professional magicians. Contacting with Zero and Ichi as Guardian, Nina began to change her mind about them. Her hobby is to stretch, or do sit-ups.
Nina is apparently extremely bad at all forms of housework, although she does not seem to realize this.
But in the end she realizes that she loves Zero. In one volume of the manga, Nina and Zero kiss when they confess their love
Nina can also be seen with her two companions in Mermaid Melody, Pichi Pichi Pitch, but only once.