Megumi Kobayashi
Tatsuhiro's classmate in high school, was the class representative back then. They meet frequently in manga, but none of them realizes the existence of each other until later. After her father died, she had to work in order to support herself and her brother, who is also a hikikomori, though ended up entangled in a shady pyramid scheme. During school, she had a very uptight personality which Tatsuhiro commented about himself to her face. After high school, she retains much of this personality, though has also become somewhat manipulative in order to survive.