Jun'ichirō Tanizaki is a member of the Armed Detective Agency and the older brother of Naomi Tanizaki who owns the ability named Light Snow. Tanizaki has a slim, average build with orange hair, hazel eyes and pale skin. His hair is parted in the middle with its spikes sweeping downwards, along with a light grey bobby pin clipped on his left. He wears earrings with the corresponding color of his pin. His attire consists of an oversized, off-white V-necked sweater with a black stripe on the collar, light blue pants, and brown shoes. A red sweater is wrapped around his waist. Tanizaki also dons a black tank top underneath his sweater. After the cannibalism, Tanizaki wears a formal suit during the agency's celebration. After the Armed Detective Agency is framed as terrorists, he suddenly wears a white hood suit and changes into a riot gear with black boots and black gloves, originally belonging to the military police. Tanizaki is arguably one of the most "average" members of the Agency, not being eccentric or loud like any of the other members. However, he does go along with their shenanigans, especially when specifically instructed by his senior members like Doppo Kunikida. He once hinted on feeling quite mediocre as a detective with an ability "not too useful for battle", albeit afterwards assuring the newcomer Atsushi Nakajima that he was able to last quite long in their rather dangerous line of work. He also does not hesitate to apologize for his behavior when necessary, specifically when he apologized to Atsushi for his rude character in his entrance exam, even when that was what was expected of him for his role. Tanizaki also has an aptitude to adapt to his surroundings, which is usually complemented by his illusory ability. As such, he is one of the agents sent in for reconnaissance missions. Moreover, Tanizaki appears to make a convincing actor, such as being a bomber even if he and Kunikida originally did not plan him to take on such role. Nevertheless, he has the occasional tendency to get nervous. He admitted being quite nervous whenever he goes to the library that serves as one of the Ministry of Home Affairs' secret bases, as well as when he anxiously flew a plane by himself and was referred to as the "wimpiest in the east" as complemented to Atsushi being "wimpiest in the west". However, he cares deeply for the well-being of his fellow Agency members, but he has a very fragile sense of morality, in which he quickly takes the path that is most likely to preserve himself and the Agency, even if it includes highly immoral behavior, including harming civilians, aiming to kill his enemies, and planning on joining the Mafia. Such impulsive actions risk endangering even his own colleagues, the Agency's reputation, and Yokohama as a whole, making Tanizaki one of the more dangerous members of the Agency in terms of liability. Despite being the humble and somewhat carefree type, Tanizaki would get extremely violent and bloodthirsty towards those who hurt his sister Naomi. He tends to get embarrassed by his sister's constant antics and physical intimacy, but he nonetheless cares deeply for her. He even stated that things such as morality, ego, and pride do not matter to him compared to Naomi and would gladly burn the world for her. Even against the Mafia's Black Lizard commanders, Tanizaki did not waver in displaying his murderous intent and threatened to kill them should they ever lay a finger on Naomi.