No one had ever bothered to tell Armin that Eren Jaeger was trouble.

It was partially his own fault, he supposed, for falling in with him and Mikasa. Somewhere between overhearing his mum telling the neighbours back when they first moved to Berlin that his Gymnasium was "the good one, even if it's in the rough part, y'know" and having his head so far into a stack of books that he forgot to make friends with anyone, Armin became convinced that his life would be pretty normal, and that the people in it were pretty normal too, if not often entirely inconsequential.

Even once Eren had succeeded in turning his entire life upside-down, there would still be a lot of people who couldn't see Eren as Armin did; as the whirlwind of anger, bad puns and fast food. This was because Armin noticed too much. Or, rather, he couldn't help but notice Eren and only Eren.

Eren and Mikasa joined Armin's class part way through the term, far enough away from the Abitur for them to slip seamlessly in to the course of work, but close enough for other students to sink away from them in favour of revising economics or political science. Mikasa had hold of Eren's hand as they stood in front of the French teacher on that fateful Tuesday morning, and Armin found himself mildly irritated that Jean was poking him, concerned as to whether that cute girl was with that weird-looking boy.

No one would assume that Eren Jaeger was or ever would be trouble because for the first few months of his integration at the school, he didn't say anything to anyone. At first Armin thought it was merely because no-one talked to him. The way he held himself in his worn-out jeans said he wasn't interested, his messy hair said he wasn't bothered, and those piercing eyes of his- one green, one yellow, with tiny pupils that drew any glance out to a stare- said he was different. That was until Marco asked him how he felt about the book that had been assigned for German as they were packing up to leave, and he just shook his head.

"No… You've not read it?" Marco looked confused, and Armin saw Eren blush as he shook his head again.

"So you have…? I… Ah, I'm sorry I asked, nevermi-"

"Oi, Eren," came a voice, and Eren's head whipped round so fast that the way the tufts of hair at his crown pointed changed, "What's your problem? Marco's just trying to be nice, jeez." Jean had his rucksack over one shoulder, and was leant on Marco's desk in a way that, in any other situation, would be the pose for asking Marco to go to the cinema at the weekend.

The moment in which Eren turned back around was the moment Armin knew he was about to watch something unfold. It really wasn't anything to do with Jean: it merely became obvious that Eren's reactions in social environments were different to anyone else's. Something eventually would have antagonised what came next, as judging by the way Mikasa advanced towards them from the corner by the window, this sort of thing had happened before.

"What the hell man, don't ignore me. You're kind of rude-"

It was almost a textbook fight, if it weren't for the fact that Eren was the least textbook boy in existence. Jean put his hand on Eren's shoulder, and the moment it made contact, the shorter boy went rigid and slapped his hand away. There was a ruckus as Jean tripped on his own feet and his thigh made contact with the table behind him: an action which only served to further knock his balance and create a painful metallic clatter as his displaced the chair into the opposite table leg.

That was it. Jean lunged at Eren, sending him sprawling over his own chair and landing at Armin's feet. He squirmed violently as the room erupted into chaos- Jean shouting at Eren, Marco tugging at Jean's shoulder, Armin and Mikasa trying to pull the pair apart while people who had been in the process of leaving for the weekend came to see who had started fighting. All the while, Eren had said nothing.

It was a strange place to have an epiphany, a shouting match cum teenage brawl, but seeing how suddenly violent Eren became when in close proximity of a person made something click in his brain. He understood on a basic level that Eren had social anxiety, but the events of the following split second reminded him that he'd only ever have a basic understanding of how Eren's mind worked.

"GET THE FUCK OFF OF ME HORSEFACE!"

And that was the first time Armin heard Eren speak, a moment in which his actions matched up directly with the fire in his scowl. It was also the first time he'd ever seen Jean get punched so squarely in the face. It did the trick, as Jean yet out a startlingly high-pitched yelp, and Eren saw his opportunity to bolt out the classroom door, stumbling slightly as he went. Mikasa, as Armin would come to learn, was hot on his heels.

Armin didn't have to get involved. He knew that. But Eren had left his bag, and Armin's heart was pounding with adrenaline from having Jean push him away during the kerfuffle.

Jean could have told him that Eren Jaeger was trouble, and seen as Armin kind of liked Jean, he might have taken his advice and stayed back. However, this was not to be. Perhaps it was just that Armin's fate was tied to Eren's, but maybe Jean was just a bit of a blockhead when it came to cause and effect. Either way, Jean's reaction when Armin picked up Eren's rucksack as well as his own was not the right one, holistically-speaking.

"Armin, what the fuck?"

"I know you don't mean it Jean," his hair flicked as he turned around, "But sometimes you can be a real douchebag."

Armin was too preoccupied to appreciate the satisfaction of leaving a room on a line like that; particularly to a boy he was often told was considered to be one of the popular boys (which never made sense, seen as Jean only really hung out with Marco and Armin). If it weren't for the fact it was a Friday and half the students had already disappeared to catch the buses going out of town, Armin might have been a temporary legend the following morning.

Armin found Eren and Mikasa sat under the stairwell a few corridors down from their classroom.

"Um… Hi, sorry. I… Eren, you forgot your bag."

There were a number of reactions Armin had been expecting from the newbie with social anxiety in this situation, but a smile was not one of them. He was taken aback, particularly as beside him, Mikasa seemed to have doubled in her wariness of Armin since leaving the classroom.

One thing Armin did notice was that Eren's left hand had hold of his right wrist. Or, rather, he didn't remark this until he let go to take his bag from Armin, who was still a little frazzled from being smiled at by this strange yet ever more intricate individual, and there was blood on his finger. Fresh, crimson blood.

"Eren, are you OK?" Armin wouldn't admit he panicked, but some sense of culpability kicked in along with his hyper-logical though processes and he found himself dropping to his knees. However, he realised he might have made a mistake as Eren shrank back, tensing.

"I'm sorry- ah, should I go?"

Eren held his eye contact for a few seconds, before, surprisingly, shaking his head.

"So you're OK with this kid seeing this?" Mikasa gestured to his wrist. With her softly-spoken yet sharp tone of speech, this almost sounded like a threat, but something about the way she looked at him and how he trusted her told Armin otherwise.

"It's Armin, by the way," he said, quieter this time. He could feel himself calming down as the noise of the students down the corridor lessened.

Tentatively, Eren removed his hand from his wrist and peeled the bloodied sleeve of his jumper back. To begin with, Armin was confused as to how a simple grapple could draw blood. It was then that he made out, underneath the already dried blood, the straight cuts running in a neat little row, and his heart dropped.

Between them, Eren and Jean had managed to reopen wounds that Eren had inflicted upon himself.

It was only then that the full weight of what Armin didn't understand became apparent to him.

Eren hadn't said anything, but he had given him those most warming smile even at a time when he was feeling vulnerable and pumping with anger; and, in doing so, had made Armin feel more accepted and valued than he'd felt in a long time. How could someone who held someone like him in such high esteem hate themselves so much as to do this to themselves?

The worst part was the fleeting glance Eren shot Armin that was dripping in guilt. Eren had no reason to feel guilty. It pained Armin to think he did, on top of valuing himself so little. A more assertive Armin would have told Eren exactly how much he meant to him: only a tiny fraction of which Armin was aware of. Real Armin, however, simply lowered his gaze and tried to banish the lump in his throat that forewarned the embarrassing baby tears for which Armin was infamous.

In hindsight, he probably could have backed out then. He often considered how Eren might have reacted to that, having put enough faith in Armin to let him stay, and he hated to think about it: about a world in which to Eren, he was a mere stranger. That said, Mikasa had told Armin that what he did for Eren may have been natural kindness for him, but for Eren was something much, much more.