Soft Oak and Silver Blade

It's the black eye that gives Sojiro pause, at first. 

"Didn't I tell you not to cause trouble, boy?" He snarls out. He's not worried about Ren, he's not, he's worried about what this will do to his shop's reputation if he lets troublemakers hang around. 
It looks like Ren is about to protest, to argue that it wasn't his fault, but smartly, the lad thinks better of it. "Yes sir. You did say that." 

"And what did you do, boy?" 
"I got into trouble. I won't do it again, I promise." 

Sojiro just lifts an eyebrow, and waves him on his way. 

-------------------------------------------------------

The black eye was the first of many injuries that Ren came home with, but it was the only one that Sojiro caught before Ren could cover it up. He knows that anyone caught with injuries stirs up rumors, and gains a reputation. And in a country like this, reputation follows you everywhere. Before he started associating with Ryuji, his reputation as a knife-wielding maniac had already flooded through the school. After he started associating with Ryuji, it only got worse. 
Whispers of gang activity swept over the teachers, and of course students had to overhear. There weren't any gangs actually in the area, but that didn't stop the suspicions of students that thought Ren brought his small-town gang activity to Tokyo. 

The knife in the darkest recesses of his backpack was no consequence to anyone, of course. It wasn't like he would use it on anyone, just... Life hadn't exactly been easy back in Inaba, either. Akira gifted it to him on his last day in town, re-enforcing how terrifying Tokyo was, it wasn't like home, Ren, you could get hurt there! 

So he brought the knife with him. 

The only time he threatens anyone with it, he gets beaten up again. It's for self defense and that's it. He would have never ever stabbed anyone with it, but blindly reaching into his bag for his pocket knife is the only solution he can think of to get the upperclassmen to leave him alone. 

It only circulates the rumors. He gets searched at school the next day, but he was smart enough to leave the knife at Leblanc's. 
(Not home, home was back in Inaba with his brother.)
Despite Ryuji not taking the hint and calling it home anyway. 
At this point, his reputation might get him mixed up in actual gang activity far faster than Ren could go actively searching for it.

He's pretty sure his ribs are bruised, the wheezing seeming like a pretty good indication. The alley is cold and out of the way, and the upperclassmen are long gone. 
He grips the knife, unopened in his bloody palm. 
As long as they didn't touch his face, he could hide it from Sojiro. Then he'd still have a place to return to.
Just 8 more months to go. 

The medical wrap he uses to bind his ribs is old and fraying, but it's all they had in the cupboard. Despite being a doctor's office, Tae doesn't sell bandages. The convenience store only had a few left in stock, and now he's nearly out again, only weeks later. Of course, she sells super-medicine that tastes like the underside of a pickup truck, but she doesn't sell bandage wrap. 

He forgets the knife is in his bag until Ryuji goes looking through it. He's looking for notes, probably, one that's been crumpled at the bottom of Ren's bag for a few days now. Ren's barely paying attention, talking to Ann on the phone when she wasn't able to make it to the roof today. 
Ryuji pulls out the folded weapon, a soft wooden handle protecting a very dangerous blade, just about the size of Ren's palm across. 

"Dude... where did you get this?" Ryuji's face is a little bit of shock, a little bit of amazement, and least surprising, a little bit of horror. Ryuji is an athletic dropout, not a true delinquint. He's not dangerous.
Not like Ren. 

Ren snatches it back, hand racing out to grab the knife, quickly shoving it into his uniform pants pocket. "Um. Nowhere. Don't worry about it." 
Thankfully Ryuji doesn't question it, but he does seem a little bit more wary around the transfer student afterwards. 

Morgana finds the knife on his desk one day and thinks it's a toy, which scares the shit out of Ren. It's a click lock, so he's not likely to be able to open or close it on his own, but the possibility still leaves Ren shaking, even after he's buried it in his sock drawer. He scolds Morgana, but he just gives an indignant meow and licks his paw. 
Ren is glad Morgana found it and not Sojiro on a wayward trip upstairs for something on the shelf. He can picture the lecture now; 
"I told you not to get into trouble! Where did you get this?"
Ren wouldn't be able to bring himself to answer. He hasn't told anyone here about Akira. The prodigal child of the Amamiya family. Here, it was just him, and the knife that Akira gave him. 

He keeps it sharpened and oiled regularly. When Ryuji gets really into weaponry and drags him off to the airsoft store, he's infinitely glad Ryuji didn't see him buy the joint oil and whetstone. He'd needed one for a while, because he's pretty sure Akira got him a blunt one on purpose. But the upkeep and care of important items is necessary, and that knife certainly counts. 

He calls Akira once a week, after Sojiro has closed up shop and Morgana has gone to bed. The dusty old laptop that Sojiro dragged out of storage surprisingly did the trick, coming equipped with a slightly cracked, but thankfully working webcam. They'd catch each other up on the events of their respective towns, but Ren learned long ago not to show his injuries to his twin, because the other wouldn't stop fretting. The black eye he gained months prior was just further reinforcement after an hour of interrogation on what happened alone. 

Their calls were pretty standard. Ren hadn't gotten in any (more) trouble, Akira was keeping their parents happy at home. 
"Holding down the fort here," he'd say, and everything was good. 
Ren told him at the end of every call he couldn't wait to see him again. Akira would respond in kind, and their call would en.
Ren didn't always know if he meant it, deep down. The thought of going back to a family who didn't really seem to care if he was around or not was a little bit more than disconcerting. At least here, Sojiro acknowledged he existed, even if every other conversation was a lecture of some sort. Maybe if Akira could come here, instead, it would be better. 
He looks at the knife on his bedside table again. He throws it in his sock drawer. 

Both at an incredibly fast pace and slower than anything he'd ever experienced, he graduated 2nd year. 
He packs up his things, says goodbye to all two of his friends, and lets Sojiro drive him to the cross-country train. He doesn't hug the old man, a stiff not managing to convey all the feelings they had between them, and then, he was on his way home again. 
The folded knife in the bottom of his carry on dug into his leg. 

He'd be home soon enough, with an old reputation to catch up with.