Tanizaki Siblings

"For Naomi's sake, I’d gladly burn down the whole world!"

- Junichiro about Naomi to John Steinbeck.

Tanizakicest is the het and familyship between Junichiro Tanizaki and Naomi Tanizaki from the Bungou Stray Dogs fandom.

Canon
Not much is known about their past, but it's shown that Junichiro lives alone with his younger sister Naomi and nothing has been revealed about their parents, although it's most likely that they are deceased as they don't live with their children. As it was guessed by Atsushi at Café Uzumaki, Naomi and Junichiro were students before joining the Agency.

Port Mafia Arc
Junichiro and Naomi make their first appearance in episode 2 (Chapter 2) when Atsushi takes the exam to join the Agency. Junichiro played the role of the terrorist while Naomi was a victim but Atsushi didn't know it before the exam ends. After the incident, Naomi hugs Junichiro tightly and asks if he's okay, to which Junichiro replies that he's hurt because her hugs. Later at the Café Uzumaki, Junichiro apologized to Atsushi, saying that even if it was for Atsushi's exam, he was still rude to him. After that, he introduces himself and his sister Naomi. Atsushi asks If they are really siblings explaining that they don't look similar to each other. Naomi smirks and starts stroking Junichiro's cheek and belly his rub saying that she can proof it if he doesn't believe. Atsushi starts blushing with an embarrassment and doesn't know what to say but Kunikida counsels him to not ask them about this and he agrees.

Junichiro gets a call about a new mission and he with others arrives to the place where their client is. Hearing the request, Kunikida assigned Atsushi and Junichiro to the job and Naomi decided to join to, so she can be with her brother. As they are being escorted to the crime scene, Naomi teases Junichiro in various ways making him embarrassed. Junichiro tells her to stop as they are in public but it didn't work. As the client led them to a dead-end alley, they revealed it was a trap and their client turned out to be Higuchi Ichiyo, a member of the Port Mafia, who started shooting them. Naomi stood in front of Junichiro and protected him with her body. She loses consciousness and falls on him. Junichiro is worried about her and thinks of different ways to help her, but Higuchi threatens him with a weapon. In anger, he fought the woman, but was defeated by Akutagawa. Later, they were treated by Akiko Yosano after being brought back to the Agency.

BSD Wan!
In Chapter 24, while having his meal, Junichiro spills some hayashi rice on his shirt, making him anxiously think that Naomi will wipe it off for him and will give him too much of her love as she always does. To his surprise, Naomi calls out his spillage and asks him to wipe it off with some dish cloth himself, leaving Junichiro in conffused state.

At the office, worrying, Junichiro informs Atsushi and Kunikida his situation. Atsushi tells him that she may be the time for her to separate from him, but Tanizaki berates and dismisses his idea, saying with a serious face that it's impossible. He cites Naomi's recent strange habits and worries that she now probably hates him. Her absence in the office further fuels his suspicions and thinks that she can be attacked by an enemy ability. Yelling, he declares that he will search for her. Worrying, Atsushi asks Junichiro If he knows where she can be. Junichiro tells him there's no need to worry about that because he can find Naomi by smelling her scent. He runs away, leaving Atsushi and Kunikida in shock.

As he arrives at a building and opens the door of the room where she is, he sees Naomi who is taking off her clothes and along with her the other female employees, only to discover they are undergoing physical examinations, leading him to be called a pervert by Naomi.

Back at the Agency, Atsushi deduces that Naomi was watching her weight before the physical exam, which explains why she was not touching her meals and kept refusing desserts. With the police almost taking him in, Junichiro is relieved about the truth of the matter and his relationship with Naomi returns to normal, with Kunikida and Atsushi wrapping up the mystery that has now been solved.

Fanon
Tanizakicest is the only official couple in fandom. However, it's criticised by many people because of their incest relationship, making them not very popular to ship. Their relationship played a lot of attention which become a reason of some theories about them.

The first theory is about that Naomi isn't a real person and she's just an illusion made by Junichiro. However, this theory was debunked as Naomi also can get injured and was once touched by Dazai. Also, as most of the abilities, Junichiro's power also has a range of area. His ability allows him to project illusions around him, covering the affected area with snowfall and as we remember in The Guild Arc, Naomi was in Haruno's house while Junichiro was at The Agency with other members so she can't be an illusion.

In other theory, Junichiro and Naomi aren't real siblings but they pretend to be them because some people believe that Junichiro had a sister before and she died.

Quotes
"Cut it out, Naomi! I'm supposed to be work! Oww! Ahh! Wait!"

- Tanizaki Junichiro's card 0020 in Tales of the Lost

"Naomi is my sister... I'm serious, you know?"

- Tanizaki Junichiro's card 0021 in Tales of the Lost

"How dare you hurt her!"

- Tanizaki Junichiro's card 0181 in Tales of the Lost

"N-Naomi! She came to watch too...? Now I'm nervous..."

- Tanizaki Junichiro's card 0187 in Tales of the Lost

"Where does this weird world end...? Naomi will be angry if I don't come home."

- Tanizaki Junichiro's card 0355 in Tales of the Lost

"Look at this, Naomi. This tart is so pretty, you almost don't wanna eat it. You can even see how fresh the fruits are."

- Tanizaki Junichiro's card 0399 in Tales of the Lost

"What's that, Naomi? You want to feed me? N-no! Don't you see all these people looking?!"

- Tanizaki Junichiro's card 0399 in Tales of the Lost

"Fufu, I guess Naomi liked it. She seemed to really be enjoying herself. I'm glad."

- Tanizaki Junichiro's card 0399 in Tales of the Lost

"That should do it for snacks. Alright, now we can have some fun! I'll take one... Hey, I can eat on my own! Jeez, Naomi... Fine."

- Tanizaki Junichiro's card 0424 in Tales of the Lost

"... Morals? Sure, the Agency has morals. But when it comes to Naomi, that's a different story..."

- Tanizaki Junichiro's card 0481 in Tales of the Lost

"Naomi, that mask looks good on you! Oh? You like mine, too? But I'm sad I can't see your face... No, stop! It's a masked ball, okay?!"

- Tanizaki Junichiro's card 0493 in Tales of the Lost

"Take my hand, Naomi. And watch your step, it's dark. H-hey, don't cling so tightly or we'll fall...!"

- Tanizaki Junichiro's card 0493 in Tales of the Lost

"Naomi, thank you for always being there for me. No matter what happens, I will protect you."

- Tanizaki Junichiro's card 0519 in Tales of the Lost

"Mmm, delicious! Poor brother, I shouldn't keep these tasty treats to myself... I know! I'll feed them to you! Say, "Ah~♡"

- Tanizaki Naomi's card 0550 in Tales of the Lost

"Hmm, so it means "devotion" too... The only person I'm devoted to is Naomi. To me, Naomi is irreplaceable."

- Tanizaki Junichiro's card 0559 in Tales of the Lost

"What a magical sight... I'll have to bring Naomi here next time."

- Tanizaki Junichiro's card 0574 in Tales of the Lost

"Sorry for the wait, Naomi. Let's eat before it gets cold. You look so happy when you eat my food. It makes cooking it all the more worthwhile."

- Tanizaki Junichiro's card 0604 in Tales of the Lost

"It says that shikigami protect diviners! Naomi, if you become one, then it would be alright for me to be a shikigami and protect you."

- Tanizaki Junichiro's card 0616 in Tales of the Lost

"With a uniform as cute as this, I would very much like for Jun-sama to see it as well!"

- Tanizaki Naomi's card 0630 in Tales of the Lost

"Atsushi-kun is painting a picture as well. Heh, that might be a cute idea. In that case, I will too... How is it? Naomi tells me I'm talented, but I don't often get the chance to paint in front of others, so it's a little embarrassing."

- Tanizaki Junichiro's card 0687 in Tales of the Lost

"It's a snowman! Whenever it snows in Yokohama, Naomi will make little ones. Aw~... I should've brought her with me. She'd be able to pick pretty colors better than I could."

- Tanizaki Junichiro's card 0687 in Tales of the Lost

Trivia

 * Currently, this is the only canon ship in BSD fandom.
 * Naomi is a character based off from real life Junichiro's novel where the two main characters fall in love with each other.
 * In Tales of the Lost, Junichiro and Naomi often drawn together in cards and they often talk about each other in game.
 * Junichiro can find Naomi by smelling her scent even If she's in a very long distance.