Kikuri was the first and only person from Ai's own world that showed up in Mayfield. She was in Ai's house as her little sister, which suited her well as back home Kikuri acted like an annoying little sister to Ai all the time.

In Mayfield, Ai tried to protect Kikuri as best she could. Which could be difficult at times. Ai cared a lot for the little girl, even as Kikuri destroyed things she liked and had a habit of kicking Ai's friends and saying Ai didn't need anyone but her.

She was droned and Ai refuses to believe that she is not safe at home. This is more for her own emotional stability because if she thought Kikuri was still trapped her, she might lose control of her emotions again.