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. In the manga, Tanizaki also dons a black tank top underneath his sweater.
Tanizaki is shown to be the humble and somewhat carefree type, yet he will get extremely violent and bloodthirsty towards those who hurt Naomi. He tends to get embarrassed by his sister's antics and physical intimacy but nonetheless cares deeply for her. He even states that things such as morality, ego, and pride do not matter to him compared to Naomi and he would burn the world for her. He also cares for the wellbeing of his fellow Agency members, however 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, murdering his enemies, and 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.
He is very friendly and arguably one of the most "normal" members of the Agency, not being eccentric or loud like any of the other members though he does go along with their shenanigans. He is also shown to be a close friend to Atsushi, primarily because the two seem to be the more "normal" members of the Agency, and the two work together on a few cases and can fight tough opponents as a productive team, such as their fight against Lucy Maud Montgomery. Like Atsushi, he can also get nervous and be a bit of a scaredy-cat (though is not cowardly) like when he was nervous flying a plane by himself.
His ability, Light Snow (細雪, Sasame Yuki?), allows him to project illusions in a certain range of area around him, covering the affected area with snowfall.
Tanizaki lives alone with his little sister Naomi. Nothing has been revealed about their past yet, or what has happened to their parents except he was a student before joining the agency.
- He, along with several other Characters, made an appearance in the mobile game Love Heaven as a limited-time character.
- Tanizaki's dislike of earthquakes may be a nod to his real-life counterpart who had a lifelong fear of earthquakes due to his home being destroyed by the 1894 Meiji Tokyo earthquake that destroyed several major cities including Yokohama.
- Jun'ichiro Tanizaki's author counterpart was a novelist who was inspired by and wrote about a vast variety of topics but is noted most prominently for his sexual fantasies and charismatic female protagonists that he created (also a likely influence for the behavior of Naomi, who is named after one such protagonist). His ability is named after his novel on the lives and social state of three sisters during the war, named Sasameyuki (light snow) but translated as The Makioka Sisters in English, due to difficulty in translating the intricacies of the Japanese title appropriately.
- In Season 3 Episode 9, Ryūrō Hirotsu comments that his ability is perfect for assassination
- Bungo Stray Dogs Manga: Volume 3.