Megumi Hidaka attends fifth grade in class 5-2. She requires glasses to correct her poor eyesight, struggling to see clearly without them. Physically, she stands out among her female classmates due to her more developed figure, a source of self-consciousness particularly focused on her breast size.

She maintains a constant vigilance over her weight, fixated on keeping it precisely at 35 kilograms. This preoccupation leads her to monitor the scale obsessively, reacting with visible distress upon seeing an apparent three-kilogram gain—only to later discover the scale was off-balance.

Her personality leans towards carelessness, making her easily fooled by her surroundings. A defining incident saw her frantically accuse male classmates of stealing her missing bloomers, only to realize with embarrassment that she had been wearing them all along, highlighting her forgetfulness and impulsive nature.