I was talking with my sister and we started talking about the Tanizaki siblings. We came up with, when Junichiro was younger Naomi died. He refused to accept the fact that she died so he now uses his ability to fake her being alive.
Well have fun with this little angst shot. :)

     Jun'ichiro walked down the busied street, Naomi by his side. She tilted her head slightly giving her brother the biggest and brightest smile. He return it the best he could. She hopped a few steps forward, turning on her heel to face him.

 "Come on, we're gonna be late!"

 She held her hand out for her brother to take. Jun'ichiro chuckled, accepting her hand. He missed her hand by near inches, and stumbled forward as Naomi gigged. 
He regained his balance with a big sigh.

 "You gotta be more careful big brother"

She giggled once again with a big smile on her face as she continued to walk with her brother.

The two teens made their way to the agency. Jun'ichiro pushed the door open, allowing his sister in before himself. Naomi greeted the agency members, like she did every morning. Skipping her way to her desk. Junichiro watched her skip off and walked to his own desk, ready to start another day. He wondered if it would be a more calm day or one of those really chaotic days they had fairly often. He sat down, opening his laptop up.
A few hours passed, Jun'ichiro stood up to stretch. He raised his arms gaining a satisfying crackfrom both arms. He brought them back down and started his way towards the door. It was around lunch so he was heading to the café on the floor above them. Dazai watched from his seat as the teen walked to the door. He stood up, stretched both arms out by his side and ran up to the boy. He brought his hands to his shoulders, forcefully pulling the boy back.

 "Hey Tanizaki-kun~"                                                                                                                                                    

 Jun'ichiro jumped from the sudden contact, he hadn't heard the older man coming up behind him.

"Ah-do you need something Dazai?"

 He turned his head slightly, looking back at the brunette.

"Do you think you could run to the store for me? Atsushi's off somewhere and I have paper work. So I can't really go" 

Dazai may have said he had paper work but, they both knew he wouldn't do any of it.

"Uh s-sure. What do you need?"

 Dazai smiled wide and let go of Tanizaki's shoulders.

"Thank you!"

Jun'ichiro smiled sheepishly, not knowing what he just signed up to do.

 "So, Yosano needs some supplies, I don't really know what she wants but I'm sure she'll be happy with whatever"

He turnes on his heel and skipped off to the couch definitely going over to do paper work. Jun'ichiro sighed and walked the rest of the way to the door. He turned the doorknob and walked out.

 
Due to the fact that he didn't know what he was supposed to pick up or even where he was supposed to go, he took a little longer than he would have liked. Once he had contacted Yosano, to figure out where he was going and what to get, he was pretty quick. But, because it had taken so long to get ahold of her it was now almost 5:30. When he arrived back at the agency only a few members remained. Kunikida, obviously doing the paper work Dazai had failed to finish. Yosano, since she said she'd wait for her stuff. And the president, as he was the president and usually left last. Jun'ichiro quietly walked into the infirmary.

 "Uh.. I brought the stuff you asked for"

Yosano turned around in her black swivel chair.

 "Ah thank you Jun'ichiro"

He placed the bags of supplies on the white desk near the door.

 "So, you ended up running my errand, sorry about that."                                                                                  
The older woman walked to the bags he had placed to see what he brought.  

"Its no big deal"     

He raised his hands to protest, in all honesty he hadn't really mind. Yosano looked up from the bags and smiled.                                                                                                                                                                    

"Well how 'bout I repay you, do you have any inquires?"                                                                

Jun'ichiro slightly jumped back, he looked to the side avoiding eye contact. Subconsciously, he pulled at his sleeve, the teen had tipped on his way back. He scraped his arm on the sidewalk, it wasn't that bad but, he knew it didn't have to be bad for Yosano to take action.   

"Nope I'm all good, thanks anyways"    

He stepped away and turned to the exit.                                                       

"Have a good evening Yosano-san"                                                                                                                        

She nodded in response as he disappeared from the infirmary. She sighed to herself and turned back to her chair.

"Damn, I was really looking forward to healing someone. I should have really checked his arm"

Jun'ichiro gathered anything he needed from his desk before exiting the building. He walked down the now quiet streets. And smiled softly to himself. As he arrived home, he quietly opened the door and called out.

"Naomi, I'm home!"

 He closed the door behind him, sliding off his shoes. He awaiting his sister's greeting. But, when a few minutes had passed and the sound of his cheerful little sister ceased to exist, his heart started racing. He ditched placing his shoes neatly at the door and raced to the kitchen. No Naomi. He ran to the stairs skipping every second step. Almost tripping on the last step he took. He peeked his head into his room then hers.
"Naomi?!"
He knocked on the bathroom door, praying for a response. Nothing. Just to make sure he opened it. 

Empty.

Jun'ichiro checked the home about three more times before calling the agency.

"Hello?"

 A deep male voice rang from the other side.

"Ah, Kunikida-san, by any chance is Naomi there?"

He tried his best to sound calm to not worry the other.

 "Uh no, sorry. It's just the president and I."

 The ginger's breath hitched.

 "Is she missing?" 

He took a breath before responding. 

"I'm sure she's fine. Just running an errand"

"Alright, but if she hasn't turned up in an hour or so contact us immediately"

 "Yep, of course" 

The younger male hung up the phone. He searched once more just to be clear she wasn't hiding on him. This time he made sure to check every corner, every hidden spot, every place a small girl could hide. He ended up in his room checking in the closet for the fifth time. Upon finding nothing once again he fell to his knees and checked under the bed.  
Nothing
The curtains were closed leaving him in utter darkness. He slid to the bed, leaning his back against it. He brought his knees to his chest, and rested his head on his knees,  the warmth from his arms that were wrapped around his legs made him comfortable. Tears welled up in his eyes and slowly streamed down his cheeks, he let out a few sobs that he quietly chocked back. Minutes passed, his sleeves dampened. In a soft tone Jun'ichiro spoke. His voice barely audible.

 "...light snow..."

A soft green hue shown beside him, green particles like snow fell around him.

 "Jun?"

A soft female voice echoed through the room. He raised his head, turning it to the side.  With a small smile plastered on his face he spoke.

"Hey Naomi" 

His voice didn't match his face. Unlike the sweet smile he wore , his voice sounded colder, almost emotionless. His cheeks were flushed with a light pink. And small pinkish red dust appeared faintly under his eyes, they were closed and it made them look welcoming. They matched well with his smile. As soon as he opened them, they quickly resembled his darker tone of his voice. The dull hazel orbs sat in his half lidded eyes, his under eyes seemed darker than usual ,the darker red that was under his eyes made them look more dull and you could tell he had been crying. His cheeks no longer had that faint splash of pink instead they glistened from the wet tears that had soaked them and his sleeves. 'Naomi' sat quietly beside her brother. She tilted her head in confusion, she opened her mouth to speak but Jun'ichiro spoke first.

 "Can I have a hug?"

She slowly nodded. And brought her body closer. Jun'ichiro firmly wrapped his arms around his 'sister'. He held her tight. 'Naomi' spoke quietly.

"Are you okay Jun'ichiro?"

 Her older brother didn't respond. He squeezed her tightly once more before speaking quietly again.

 "I love you Naomi"

The small black haired teen, let out a soft giggle.

"Of course, I love you too!"

 Jun'ichiro's shoulders shook as his emotions got the best of him.

 "Big brother?" 

"Naomi..."

 The young males voice echoed through the room as time seemed to go still.
                ...

              "Goodbye"

Welp, hope you liked it. Sorry if this hit a little to hard. I promise I'll write some fluff next
Eggrollinabowl♡