Yuki Kusakabe (草壁 優季 Kusakabe Yūki ) is Takaaki's childhood friend who he supposedly 'proposed' to.
She is quite calm and caring towards others. Yuki is usually seen at night carrying around her Trash Basket Notebook. She seems to endear the memory of Takaaki suggesting that if she didn't like her new last name, she could use his instead.
Yuki has long beautiful black hair and deep blue eyes. She has a slim and tall physique.