Kiyotaka's younger sister

Kiyotaka's younger sister is a freshman at Sanada Central High.

Appearance
Kiyotaka's younger sister is slim and of average height. She has violet eyes (in the anime) and dark pink hair of medium length. She is seen wearing the Central High uniform.

Personality
She is a shy person, barely having spoken at all in front of her brother's friends. She is also polite as she apologizes to the boys for having lost her contacts.

High School Boys and Old Friends
When Kiyotaka walks up to Hidenori and Yoshitake and begins talking to them, she is standing by his side silently and holding his arm. As their conversation continues, Hidenori and Yoshitake notice her glaring at them fiercely and they mistake her for Kiyotaka's girlfriend who wants to spend time alone with him. After Kiyotaka pulls them into a nearby fast food joint, she continues glaring at them. When Kiyotaka brings up a group date he went on recently, Hidenori interrupts him for his "girlfriend's" sake, but he reveals to them that she's his younger sister who had a bad squint because she lost her contacts. At this point, she apologizes sheepishly to the boys, who collapse on to the table.

Trivia

 * Kiyotaka and his sister are the only brother-sister pair shown in the series that attend the same school.