Mayoi Hachikuji is a fictional character from the Monogatari series, created by Nisio Isin. She appears as a young girl who is a ghost, often seen wearing a distinctive backpack and a striped hat. Mayoi is known for her cheerful personality and her tendency to get lost, which reflects her backstory of being a lost soul. In the series, Mayoi encounters the protagonist, Koyomi Araragi, and helps him navigate various supernatural challenges. Her character represents themes of loss and the importance of moving on, making her a significant figure in the narrative.