A/N: I actually wrote this back in March. I was debating whether or not to post it, since this is Shin Soukoku and not Soukoku, but it has implied Soukoku in it. Plus, this fits in my Kintsugi series, so I see no harm in it. Enjoy!

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Lots of relationships have rocky starts. Sometimes one hears the other talking about the former behind their back, sometimes the two flash each other glares in hallways over a petty rivalry…

Sometimes, they constantly try to kill each other.

Now, that final one is uncommon, but for Akutagawa, it felt no less ordinary than the rest of his killing days.

Nakajima Atsushi.

The weretiger.

Akutagawa held a grudge against the young man. First and foremost, as the fabled weretiger, he was Port Mafia's main target. But more importantly, he was Akutagawa's sworn enemy. His obstacle in getting Dazai's recognition.

Akutagawa never thought he would see the day he grew...close to the weretiger.

He doubted even more he would consider him a younger brother.

But oh, how times change.

Here he was, taken under his mentors—Dazai Osamu and Nakahara Chuuya's—wings, as a son, of sorts.

And, so was Atsushi. As Akutagawa is Chuuya's underling, Atsushi is Dazai's protege.

So the two had to learn how to function like brothers.

Not too difficult a task, Akutagawa thought, and he was right. It was fairly easy to keep Rashoumon at bay and not strangle the younger boy.

It was not so easy to keep himself from growing attached to the younger boy.

~

"Hey."

The raven-haired stands in front of the white-haired, awaiting his attention. Akutagawa has never been good at being...forward.

Atsushi looks up at him, eyes big as normal. He tilts his head, like a cat, lost in wonderment.

Another thing Akutagawa is not good at is showing affection. Growing up in the slums, being brought into the mafia, it was not a skill he needed. And he isn't naturally caring like his red-headed mentor is.

But under the influence of such behavior, the boy picked up a few things.

Pale hand shaking, he lightly places it atop Atsushi's head, and gently ruffles his hair. He notices cat ears poke out from the top of the white-haired boy's head.

Must be a side effect of being petted. When you're Nakajima Atsushi, the Beast Beneath the Moonlight, that is.

"Jinko-ototo."

That came out colder than Akutagawa would have wished.

But he still said it.

Atsushi's eyes widen and he blinks slowly, twitching.

"Wh-what did you say?"

Akutagawa closes his eyes and chews on the inside of his cheek, choking down a cough.

He can't believe he's about to repeat his words.

"I said, 'Jinko-ototo.' I called you Jinko-ototo."

Atsushi blinks more rapidly, and his heart speeds up.

"O...ototo?"

He can barely speak.

Akutagawa lets out his cough and lightly clenches onto tufts of white hair.

"Yes. I see you as a younger brother. Deal with it."

Atsushi continues to stare up at the older boy, until he springs up from his seat and pulls him into a hug.

This was unfamiliar territory for the raven-haired boy. Nervously, he puts a clammy hand onto his shoulder as a weak attempt to return the gesture.

Atsushi looks into Akutagawa's eyes, his pupils wide, again, feline-like. "Then, I should probably reciprocate, right?"

"I beg your pardon?"

"Ryuu-nii."

Atsushi purrs out the nickname as he continues to look up into the dark eyes of his kyoudai, who is rendered speechless, and petrified.

Atsushi blinks. "Ah...was that too far? I'm sorry—"

"No."

Atsushi tilts his head in confusion.

"No. Ryuu-nii. I...like that. Like that? I like the sentiment. You...see me as an older brother, yes?"

Atsushi nods.

Akutagawa shivers in place, and then falls to his knees, causing Atsushi to flinch in shock.

"A-ah, are you okay?? Should I get Dazai-san and Chuuya-san—"

"I'm...happy."

Akutagawa clutches his chest and looks into the eyes of the worried weretiger.

"I feel...warm in my heart. You've made me happy."

Akutagawa twitches and raises to his knees, Atsushi then helping him to his feet.

"I hate it."

Atsushi laughs. A quiet one, not boisterous or confident. A hearty chuckle of amusement from the comment from his kyoudai, attempting to stay emotionless as per the usual.

"That."

Atsushi stops laughing. "Huh?"

"That noise you made."

"You mean...laughter?"

"Yes. Laughter. I...I want you to do that more. It makes me...happy. I like seeing the rise and fall of your shoulders in amusement. It makes me feel...like I've done right."

Akutagawa stares at the younger boy. His face shows little to no feeling, but on the inside, he wants to cry. Most of his time knowing Atsushi, he loathed him. Wanted to kill him.

But now…

Things were different.

"Put your arms around me again."

And, slowly, Atsushi pulls him into another hug.

~

"Hey, Jinko-ototo."

The two were sharing earbuds, listening to music as Akutagawa read one of Chuuya's poetry books and Atsushi spaced out, snapping back into reality when he hears the nickname bestowed to him by his found kyoudai.

"Yeah?"

"I think I love you."

The words felt weird coming off of Akutagawa's tongue. "Love" was never a word he used to express something. It was a feeling he was unfamiliar with.

Until now, when he sees the weretiger staring at him, bug-eyed, cheeks red.

"H-huh??"

Akutagawa's nose twitches. "You seem to have misunderstood."

He coughs. "I don't love you in the way Dazai-san and Chuuya-san love each other. I never, ever will. I don't even know if what I feel is...love. I don't know love. I don't think I'll ever know love. But...what Chuuya-san told me is, when one enjoys something a lot. Admires it. Wants to protect it. Now...I've seen the way he is with Dazai-san, and they're all touchy-feely and they hold hands and kiss, and I don't want that. I don't want any of that. But...I enjoy you. I enjoy your company. I admire you and your strengths and your weaknesses. I want to protect you with my life. I don't love you in a clingy...romantic way. I love you in a way a brother would love another brother."

He coughs a few more times. "...did I say that right? And why are you crying, Jinko?"

Atsushi sniffles and wipes his tears. "Yes, yes you did. Thank you...Ryuunosuke. I also love you, like a brother. Thank you."

He laughs through his tears. "Permission to give you a hug?"

Akutagawa sighs, but a tiny smile tugs on his lip. "Go ahead...Atsushi."

And Atsushi throws his arms around the raven-haired boy, sniffling into his shoulder, never wanting to let go.

"You will wash the snot out of my shirt later."

Atsushi laughs again. This laugh not forced like the prior one. This laugh 100% genuine. "Yes. Yes I will, Ryuu-nii."