Erio is Makoto's first cousin, and Meme's daughter. One day, when coming home from school, she mysteriously disappeared for six months only to be found floating in the sea with no memories of what had taken place at all. She began having an extreme fascination with aliens, believing herself to be an alien investigator monitoring humans. Following an incident whilst trying to fly on her bike where she broke her leg, she started to constantly wrap herself in a futon. Her mother would constantly ignore her and pretend she didn't exist. This was first shown when Makoto and Meme got home. After accepting that she is human she begins to use her futon less, only when she's uncomfortable. She also begins to do more things that a normal person would do, like going to work and playing baseball. She likes to watch to the night sky with a telescope together with Makoto and often draws what she sees on a notebook.