Iwanaga Shouko

Hobbies: Taking care of a certain animal; collecting beautiful stones
Likes: Her mother; Jacos
Hates: Her male classmates

Kousuke's cousin.
She has a gentle personality like her mother, but she is quiet and shy, and rarely speaks to Kousuke. One of Kousuke's "part-time jobs" is to help her with her studies, but the awkward relationship makes it difficult. Shouko was very young when they first met before, and she barely remembers him. To her, Kousuke is just an older cousin whom she does not know well.

She was a bright girl back then, and seems like something is troubling her mind recently...

Based on the official website