Yukizona Harumi holds the rank of First Grade Armed Librarian within the Bantorra Library organization and ranks among its five most powerful members. He is formally designated the successor to the position of Acting Director, following Hamyuts Meseta.

Despite his formidable combat capabilities and high rank, Yukizona battles severe, chronic illness that leaves him physically frail. This condition necessitates partial covering of his face, likely due to medical needs or symptoms. His younger sister, Yuri Harumi, serves as his constant companion and caretaker, using her unique ability to temporarily alleviate his symptoms. However, her power provides only transient relief, not a cure for his underlying condition.

Yukizona possesses significant awareness of classified truths within the library, including knowledge of the existence of "Heaven," a secret known only to a select few. In combat, he relies on Yuri not only for medical support but also as his direct battle partner; she engages enemies with firearms while fighting alongside him. Their partnership is integral to his effectiveness given his physical limitations.

He actively participates in the library's major conflicts against adversaries like the Shindeki Church, operating within the constraints imposed by his health. No information exists regarding his ultimate fate or specific character evolution beyond these core attributes and his involvement in the primary conflict.