Tsubaki Uehara

She is a picture book author who is the mother of Plum and a childhood friend of Hotaru Yūyami. She is raising Plum as a single mother, but is not good at cooking and can only make rice balls. When she was a child, she had feelings for Hotaru Yūyami, but could not honestly express them, instead teasing and playing pranks on her. Because of this, Hotaru Yūyami was always just puzzled by her actions. Even now, she still seems to be a fan of Hotaru Yūyami.