As a result of the emergence of dragons, known as monsters, the world experienced significant changes. Soon after, individuals with supernatural abilities linked to dragons, referred to as "D," began appearing among humans. One such individual was Mononobe Yuu, the only male "D." He found himself thrust into Midgar, a school where female "D"s congregated, and witnessed one of the students' naked bodies, Iris. Additionally, he reunited with his sister Mitsuki at this institution. The story revolves around Yuu's journey to become the strongest assassin despite his initial incompetence, as portrayed in the unfolding narrative-Unlimited School Battle Action!
Juuou Mujin no Fafnir has been digitally published in English as Unlimited Fafnir by Kodansha Comics USA since January 19, 2016.