Like Yumiya Rakko, her family name "Yumiya" (弓箭) literally means "bow and arrow", an apt name for someone who knows archery. Her given name "Iruka" (入鹿) can be interpreted as "dolphin".
She has long wavy hair, which she ties with a ribbon at the back. Her fringes cover the right side of her face, and she also wears a traditional Japanese hair ornament, the kanzashi. As she is a member of the archery club, she wears the traditional garb for it. When wearing her Tokiwadai uniform, she wears stockings instead of stocks.
As an ojou of Tokiwadai, she has a serious and refined personality to her, and is approachable by the other girls. However, she carries a dark side as she is able to successfully plan and take down Shokuhou Misaki.
She was part of Clone Dolly, a workshop created to make geniuses. One day, she and her older sister, Rakko, visits the Third Laboratory: Ideal, where they meet Mitsuari Ayu and later Hokaze Junko. Iruka tries to approach her, but is told by Junko not to come close as she is a danger to others. Suddenly, Junko gets a headache and she staggers next to the wall, cracking it. Ayu informs her that Junko became a Level 4 from a Level 2 in only two months, and Junko later proves her power by destroying a punching machine. Iruka is impressed by this, and Ayu tells her that everyone admires Junko and the facility is meant to raise a Level 5. Hearing this, Iruka thinks she can be like Junko as well.