Description: (spoiler warning ahead)

She is supposedly Taruto's consciousness, who's been talking to her in thoughts, helping Tauruto along the way.
Her character wasn't thoroughly explained much in the anime, which was left mostly a mystery as to how she was hiding in side of Taruto's body, or how she managed to be merged with her older twin sister Taruto and hiding her identity.
Pie had a more major role by the final, where she revealed to Taruto that she is her younger twin sister. According to what Pie mentioned, both were in the basket deployed in the river. Pie later revealed she was the one who's been responsible for Taruto's magic powers disappearing.
Pie wields a magical staff. She is more secretive, soft spoken, sophisticated and smarter than her sister .

Likes: giving useful and helpful advice, keeping secrets, helping Taruto.
Dislikes: Taruto being in danger.