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 violent 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. He also cares for the wellbeing of his fellow Agency members.
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.
Tanizaki debuts posing as a hostile enemy with a grudge against the Agency, threatening to bomb everyone and having his sister pose as a hostage. This charade acts as Atsushi Nakajima's entrance exam into the Agency.
After the incident, Tanizaki apologized to Atsushi, saying that even if it was for Atsushi's exam, he was still rude to him. This fact shows off how much of a caring person Tanizaki can be. It was also when he had told Atsushi that he too worked as an assistant of sorts at the agency.
He and Naomi later attend Atsushi's first major mission, assisting a woman claiming to be stalked. The mission ends in an ambush orchestrated by Port Mafia, and the woman violently shoots at the trio. Naomi saves Tanizaki's life by using herself as a shield. Naomi's dire state makes Tanizaki snap, and he uses Light Snow to counter Higuchi's assault. Just as he's about to crush her neck, Ryunosuke Akutagawa uses Rashomon, which severely injures Tanizaki, leaving Atsushi on his own against Port Mafia's hellhound.
With the help of Akiko Yosano's ability, Tanizaki makes a full recovery. As the struggle with Port Mafia goes on, he investigates one of the cargo ship areas during the Agency's rescue mission for Atsushi, only to find all crew members slaughtered by Akutagawa.Bungo Stray Dogs Volume 3, chapter 10 Thankfully, Atsushi defeats the latter. In the aftermath, Tanizaki is among the members welcoming their newest member to the team.
This peace is short-lived. Following Port Mafia's failed kidnapping, The Guild makes its move to obtain Atsushi themselves. Once more accompanying Atsushi with his sister to investigate Kenji Miyazawa's disappearance, the trio breaks when Lucy Montgomery's ability traps Naomi. A panicked Tanizaki tracks Lucy down, but she quickly traps much of the public in her ability. Despite his ruthless desire to save Naomi, Tanizaki also falls victim to Lucy's ability. However, Light Snow creates a false door, tricking Lucy. Together with Atsushi, Tanizaki succeeds in freeing Naomi and Kenji. Later on, Tanizaki uses Light Snow to hide the helicopter he pilots to give Atsushi cover so he can board Moby Dick and defeat Fitzgerald once and for all.
After the Guild incident, Fyodor makes his move using a mysterious ability-user assassin that allows Pushkin to infect both Mori and Fukuzawa. Once it becomes unavoidable that one of the infected must die to save the other, the Port Mafia and Agency enter yet another heated war to save their respective leaders. Tanizaki personally goes to where Mori lies unconscious and helpless thanks to the disease, but Koyo stops him and nearly injures him. Soon the struggle seemingly ends in Port Mafia's favor, having caught Tanizaki, but Tanizaki's spirit remains unbroken and unfazed, unsettling the executive members a great deal.
- 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