Kawanishi Ruka

She is a sophomore at Tamano Gakuen. Her parents divorced several years ago, and her father, who took her and her younger sister in, evaporated, leaving her with debts. She is now somehow able to attend the school with the kindness of her relatives and earns her living by working part-time jobs. The Neyagawa family is also concerned about Rio's childhood friend and takes care of her in any way they can.

In order to support her young sister, she wants to work immediately after graduation, so she spares no time to study and learn various skills at her part-time job. She is generally cheerful, good-natured, quick-witted, and considerate, and has a good number of friends. However, due to her family environment, she is not allowed to get too deeply involved in her own affairs, and she tends to have shallow friendships due to her financial problems.

She is positive and quick to make up her mind, and naturally tries hard to do what is beneficial to her. When Rio's maternal grandmother offers to take care of her younger sister while she is away, she feels bad about refusing, so she takes advantage of the Neyagawa family's kindness and comes aboard.