Owner of Naganohara Fireworks in Inazuma. Known as "Queen of the Summer Festival," she excels in her craft of creating fireworks that symbolize people's hopes and dreams. Yoimiya, like the rest of her family, is loved by the people of Inazuma City for the fireworks she creates. She is also loved by children due to her friendly hands-on approach with them. She is somewhat of a fast speaker, and despite being the primary provider of fireworks, is also known to be quite reckless and unprepared.