Nina is the main character who accidentally swallowed a magic pearl. Now, she has Ichi and Zero living in her closet, which has been transformed into a good-sized apartment. Various teams are constantly chasing her because they need the pearl to pass their exams and become professional magicians. Nina finds herself falling for both Ichi and Zero but struggles to choose between them. At twelve years old, she seeks a cute boy who can protect and love her.
A 7th-grade girl with an aggressive personality, Nina's interactions with Zero and Ichi as her guardians begin to change her perspective. Her hobbies include stretching and doing sit-ups. Despite being extremely bad at all forms of housework, Nina seems oblivious to this fact.
Ultimately, she realizes that she loves Zero. In one volume of the manga, Nina and Zero share a kiss when they confess their love for each other. Additionally, Nina can be seen with her two companions in Mermaid Melody Pichi Pichi Pitch, though only once.
