Sanae Minami is a high school student whose 145 cm stature, long black hair, and violet eyes create a noticeably younger appearance than her peers. She remains quiet, reserved, and timid, habitually keeping distance from others and avoiding social contact. Pronounced skittishness and shyness contribute to an impression of vulnerability and a need for protection.

Chronic health issues require her to carry regular medication, initially presented as vitamins in a pill case. Medical advice suggesting countryside air could improve her condition partly motivates her participation in activities at Kanenone. This illness causes general physical weakness and a fragile constitution.

Her youthful demeanor inadvertently draws attention from Tenjin, who harbors a particular interest in "little sister" archetypes. His enthusiastic, unconventional advances consistently frighten her, reinforcing her anxiety around boys. She exhibits the most fear toward male classmates, especially Tenjin, though she gradually develops trust in Yuusuke due to his helpful, non-threatening behavior.

Among female peers, she forms a friendship with Wakaba, who helps draw her out of isolation. They bond over shared naivety about the world during lighthearted interactions, though Sanae rarely initiates activities independently. This dynamic contrasts with her otherwise withdrawn nature. Her role in group settings remains secondary, often framed by her reactions rather than proactive contributions.

No significant character development or altered circumstances occur across related media appearances. Her interactions consistently reflect discomfort with overt attention, particularly romantic or obsessive advances, while highlighting tentative connections within trusted friendships.