Rikka Hiiragi is a female second-grade elementary student who just got transferred into Seiyo Academy. She has a high spunk and energetic character and always being distracted whenever someone was talking to her. She is very kind and caring to poor things, for example, watering a plant in the sidewalk and saving a kitten from a tree. Ever since when she first met Amu Hinamori and the Guardians, her dream goal is wanting to become a Guardian herself.

Some days later, Rikka finally got what she dreamt for as she became a Guardian Apprentice, alongside with Hikaru, and she is one step further to become a full Guardian. She secretly rescuing some X-Eggs without the Guardians knowing about it.

Rikka has the rare ability to see Shugo Charas and to communicate with X-Eggs without having her own Heart's Egg.

Rikka's voice actress is Erika.