Naoko/Nikki is one of Sakura's friends. She's into the paranormal and UFOs.
She's quiet girl and she loves to read, especially ghost stories. She's not very athleticly inclimed like Sakura, and she wishes that she didn't have to take Gym, as illustrated in the Shot card episode and the loop card episode.
In the episode with the create card, we get to see how her imagination works, it's kind of weird!