Hamako Shihonmatsu is the animation director of Studio Petit. It is mentioned though that she once began with the post of an animator.

Hamako is a high-class specialist. She may seem cold and unapproving at the first sight, but she is actually caring and warm-hearted. She was the one who gave Kuromi some useful tips and advices when Kuromi was in need. Hamako also feels responsibility towards the studio's product and wishes it to be at the highest level possible. She prefers not doing the work at all rather than doing it badly.

Hamako is a heavy chainsmoker. However, she tries to quit as she sees smoking women as "not pretty".