Hajime Narumi is an exorcist affiliated with the True Cross Order's Kyoto Branch. He is a well-built man with spiky black hair and typically wears the standard True Cross uniform with short sleeves, often complemented by the traditional adornments of a member of the Myōō Dharani. Within his unit, he takes on the role of the primary attacker, working in tandem with his colleague Haruta Shishamo. His personality is defined by composure and steadiness; he possesses nerves of steel and is not easily agitated, even by the carefree attitude of his squad leader, Juzo Shima.

During the events of the Impure King's revival in Kyoto, Narumi participated in the branch's offensive against the powerful demon. When the traitorous exorcist Saburota Todo appeared on the scene, Narumi and several other exorcists went to support Yukio Okumura in the ensuing battle. Operating as part of Juzo Shima's squad, Narumi and Haruta Shishamo launched an attack against Todo. Their primary objective was to buy precious time for Juzo to land a decisive blow, but their efforts were cut short as both were swiftly defeated by the formidable Todo.

Narumi holds Meisters, or master qualifications, in both the Knight and Aria paths of exorcism, a combination he effectively utilizes in combat. He fights using a K'rik, a traditional Buddhist ritual tool, and can cast spells upon it. One of his notable techniques is the Flame-Tipped Vajra Spear, with which he materializes a spearhead of blazing fire at the top of his K'rik to strike his opponents. Outside of his duties as an exorcist, his hobbies include mountain biking.