A/N:
I don't know I just had this idea in my head since last night, can't remember where I even got it from. This takes place like days before Yelena's first meeting with Eren. If anything doesn't make sense it's because I was a little loose with the timeline and haven't read those chapters in foreeeever, so open minds everyone!

XXX

Levi had always been protective of the people he cared about. From getting into fistfights for Farlan and Isabel in the Underground to defending Erwin's strategies to the clowns running the military. The feeling ran deep in his bones and felt like acid filling his veins every time it struck him. Once it had come with agonizing cries of anger, now it simply set his eyes alight with an indescribable fury. After losing so many people, he had thought the feeling would fade, replaced by numbness, but this wasn't the case. There were always new people making a mark in his life, always someone he couldn't bear not to protect. He knew it was wishful thinking to believe that this time he wouldn't fail, but he persisted nonetheless.

With Eren it was different. Even before revealing himself as a shifter, the boy was highly skilled in combat. If he struggled at first it didn't show with how determined he had been to perfect every move, to ace every drill. It surely wasn't like he needed defending either, the young man had no qualms facing down anyone who would object to his goals or his way of reaching them. It wasn't like Levi could show favouritism towards him anyway. He was supposed to be the unmoving, ruthless Captain of 104th. Humanity's Strongest, expected to kill the shifter in cold blood at the first signs of trouble. So the raven continued to guard his expressions and let Eren get into whatever trouble he would inevitably get into without so much as a second glance.

In the night though, sleeplessly staring at his ceiling, he was stripped of title and rank, he was simply a man, simply Levi. That is when he would let his mind wander, plan for subtle ways he could protect the one he dared not admit he cared for. At first, it was more overt ways to keep the boy from getting killed. This he was allowed to worry about, Eren was his charge after all. He didn't call attention to the fact that he always made sure that either he or Mikasa was with the young man during missions. The rest of the world was not nearly as oblivious as Eren was to his so-called sister's true feelings toward him. And even though he had found himself feeling more and more possessive over the brat, his brat, Levi was not jealous. In fact, he was glad there was another competent person who felt the same way he did. He was reassured in the knowledge that someone else would also lay it all on the line to ensure Eren's safety. Levi could see in Mikasa's eyes the same acidic urge to protect. Once he had thought that perhaps it was a trait from their shared lineage. But then he thought of his uncle... Maybe not.

It didn't surprise Levi that Eren didn't see the obvious feelings of the girl right in front of him. The Captain was sure the younger man had eyes only for the Titans he swore to exterminate long ago. Even though he'd been a man for a while now, he didn't seem much interested in the hormonal exploits of his friends. He spent what little days off he had training and spending time with Arlert. Sometimes Levi would overhear them, planning out their futures. They had beautiful dreams, dreams Levi had never had the pleasure of dreaming himself, too focused on surviving the day to think about the future. Even those small moments of innocent pleasure had diminished to near none, and Eren seemed to have only one thing on his mind at all times. It pained Levi to see him so stressed and angry all the time, but what could he do? Just another thing he couldn't protect the boy from.

So he focused on what he could do. He began keeping a closer eye on Hange's experiments. Some of them were normal enough, some made him cringe in disgust. What was important was keeping them from going overboard, or lasting too long into the night. So he watched, and he silently admonished the mad scientist with glares and grunts when he was mildly displeased. When it got to be too much, too long or he just couldn't deal with watching Eren in pain anymore he would coldly cut the boy out of his Titan, or grab him by the back of his shirt. "Enough. We are done for the day." he would say. It wasn't an order, it was a warning. Once he had let Hange stay alone with the boy. "I'm not going to do anything to him." they had pleaded, "I'm just going to hide and observe what he's like when he's falling asleep." Levi had run his hands over his face. "Why can't you do this in the lab during the day?"

"It won't be as accurate if he knows we're watching. Whether conscious of it or not he won't be acting like his normal self. Come on pleeeease Levi, I promise he will never even know I was there!"

Levi had sighed. "Fine." he had said. But he had barely slept and ended up waking extra early that morning. He had waited with a slightly deeper scowl than usual for Hange to appear. When they did their crazed smile and blushing cheeks did not inspire confidence. "What happened?" he had asked, a little too eagerly. If Hange noticed she didn't say anything as she opened her notebook, giggling like a schoolgirl. "You won't believe it, Levi! Eren was... well he was- he-"

"Spit it out, Four-Eyes!"

Levi had glared as he snapped, but he had been more than a little curious about what had gotten the shameless scientist to stutter of all things. "He was pleasuring himself, Levi! And he-" Huh, so the brat was more hormonal than Levi had thought. The anger had boiled inside him as soon as Hange had said the words. They were crazy if they thought they could lay a single inappropriate hand on his Eren. He would kill them. His foot had come to sweep under their legs and rest on their chest before he could think of what he was doing. He had spoken coldly, barely above a whisper, eyes narrowed in fury. "What did you do?" Hange had shaken their head violently, a small smile still playing on their lips. "Nothing Levi! Took notes, that's all. Wanna see 'em?" Levi had blinked. Did he want to see them? Did he want to know about Eren's... activities? Hange was always thorough. They no doubt wrote down exactly what the brat had been doing to himself. So many questions had swirled through Levi's brain as he backed off of Hange. What was Eren like at that moment? Was he standing, leaning on the wall? Was he in bed, hiding under the blanket? Did he purse his lips to breathe heavily through his nose? Or did he open them and let small sounds of pleasure slip out? Did he flush bright red? Did it go to the tips of his ears and right down to his collarbone like it did when he was embarrassed? Levi had snapped out of his thoughts at Hange's boisterous laugh. "Get the hell out of here." he had mumbled. He shouldn't want to know what was in that book. He would resist looking at it. He was a man of great restraint after all.

After that disaster, Levi had felt himself growing even more protective over Eren. He couldn't help shooting quick glances in his direction every now and again. He told himself it was to make sure the boy was behaving. But he could feel the way it calmed his beating heart to confirm Eren was safe. He was getting louder and bolder during the experiments, asking Hange why they had to do the things they did. It seemed to him they were torturing the shifter more than anything. But Hange always seemed to have a good reason for the things they did. He started sneaking around more as well, suddenly concerned with his subordinate's comfort. He changed the sheets on his bed more often and brought down his own, softer pillows. "The rest are in the wash." he had mumbled at Eren's inquisitive look. But he never switched them back and the soldier didn't bring it up again. He left toiletries on his bed every month, a bar of soap he had specially delivered because the Survey Corps apparently couldn't afford good soap worth a damn, and clean towels. Eren's hair was getting longer, so he left him a comb too. Over the months more gifts accumulated; shoe shine, extra toothpaste, nail trimmers. All under the guise of wanting his soldiers to be clean and composed. After particularly tough weeks of training along with grueling experiments, Levi would give Eren his portion of food, claiming he felt nauseous and that he knew the boy would eat all of their portions combined if they let him. He was ok with a piece of bread for dinner on those nights. He began preparing snacks for after Eren was done with experiments. He kept his neutral face when he shrugged at every thank you and fond smile Eren shot him while chowing down. But he couldn't help the soft glow of pride he felt at having taken care of his Eren.

Months turned into a year and over a couple of uneventful months, Levi had fallen dangerously into routine, boredom, and satisfaction. That must be why his world had to crumble. The twist in his gut, acid filling his veins, and fuzziness in his brain all hit him before Hange burst into the room. Levi's eyes snapped to theirs, and before he could scowl he saw the look in their eyes that made him freeze. He didn't know where this mounting pressure in his chest was coming from. Before Hange could speak he was already urging them to explain, "What happened?" Hange's eyes were wide, face pale. "After you left to get the snack, I asked Eren if he could cut his finger off for me. We were going to do experiments with his regeneration and whether cold weather would affect it." Levi set down the platter he was still holding and nodded for them to go on. "But he instead cut off his entire forearm. He said he misunderstood what I had asked." Levi tried to calm his fast-beating heart, Eren could regenerate limbs, he was okay, he would be okay. "The brat is always acting before he thinks." he tried to channel all of his usual unemotional coolness into the words. "I patched him up and said we should probably pick things up tomorrow." Hange seemed hesitant now, there was definitely something else. The Captain's patience was long since gone. "What? What the fuck is it Hange?" The scientist flinched, she hurried on her explanation, "It was his eyes, Levi. Something was just not right, he had this look like he- like he was already dead. And I was about to ask him about it when suddenly he-" Levi didn't need to hear more. His head was already pounding, every step resounding a thousand times in his ears. Why were the hallways so damn echoey?

Before he could process what he had done, he was in the dungeons. He was slowly approaching now, as if scared to frighten a small animal. The sight he saw upon reaching Eren's door had his body going rigid. He could barely breathe but he felt the bile rising in his throat, threatening to push past his lips. He had seen some of the most gruesome scenes in history, participated in them even. This was worse than anything he had encountered in the Underground and, he thought, even a well-trained soldier might find themself spilling their dinner at the sight. It was Eren who broke the silence. "Come in, Captain." His voice was empty. When did that happen? Sure Levi had noticed Eren's somewhat subdued energy as of late. He hadn't been eating half as much every day and his small smiles no longer appeared of their own volition. They looked forced, and tired. But everyone was tired. Every man and woman soldier or not was tired of this war that seemed to wage eternally. So Levi had pushed his concern aside and concentrated on making sure they were ready for the next mission. Levi pushed the cell door open with shaking hands. He should have been covering up his emotions as he always did, but something in him had broken at the first sight of his beloved.

He was sitting on the bed, back against the wall. His green eyes reflected the light but the fire and passion in them seemed long extinguished. He hadn't looked up at the Captain, his eyes trained on the object in his hand. His right arm hung limply beside him, forearm missing, stub covered in bloody bandages. His left arm was holding something aloft, in front of his face. Levi knew what it was but his brain still refused to comprehend what he was looking at. Eren was holding, and staring intently at his own severed hand. He held it gently by the wrist, letting the soft plip plop of the blood escaping it hit the floor. As Levi walked closer, torch in hand, he let the offending limb fall softly on his lap. Levi scrunched his nose in disgust but his eyes were trained only on Eren's beautiful sullen face. "Eren," he started, but he didn't know what to say. Nobody should be holding their own severed limb like that. More importantly, no one should have such a vacant expression while doing so, especially a firecracker such as Eren. "Do you know the Ship of Theseus?" the boy spoke. No, not the boy, this was the voice of a man. Calm, calculated, and cold. "I-I... what?" was all Levi could get out. When had he become a stuttering mess?

"Armin told me about it." Eren continued, seemingly unbothered by his Captain's odd behaviour. His eyebrows knit together as he thought. "Some ancient philosophy about a boat. I don't remember much but the point is if, over years and years, you replace every single part of a ship, is it still the same ship?" The silence seemed to cling to them as Levi processed the soldier's words. He watched as Eren stroked the cold dead fingers of his now detached hand. Levi had gotten closer now without realizing it, and he put his hand over Eren's good arm, stilling it. "Eren," he said again, this time with more force. The green eyes he fantasized about every night coming to meet his. "What is this about?" he asked. His voice was strong but warmer than he had let it get in a long time. "This was mine." Eren said, looking down at the bloody mess on his trousers, "I ate with this hand, wrote with it, fought with it. I hugged friends with this arm, patted them on the back when they came home safe. I... touched..." his voice faded as he seemed to think better of whatever he was going to say. "And now it's just... cold. Not a part of me anymore and never will be again." There was silence as Eren swallowed hard, his eyes were getting red. "Eventually, none of me will be left. I'll just be a mishmash of random parts that have never known a peaceful world."

Levi wanted to get angry. He wanted to slap the man, to tell him that some people never knew peace, and to stop pitying himself. But as he searched for words, as he let Eren's pain sink into his heart, all he felt was hopelessness. He looked at Eren, whose tears now flowed down his cheek quietly. Even that was unlike the man he had gotten to know. He would expect loud sobs to ricochet on the walls. But no such sound was heard, only the calm breathing of a man resigned to his fate. Levi felt it, all at once, the pain and the hopelessness crashing into him like a sword ripping apart his insides. He had failed again. He had not protected Eren from anything. The world continued its torturous grind until it broke him too. Even Eren, who Levi thought could never lose his passion, had seen enough for his fire to go out. "That's not true" Levi found himself saying and Eren's eyes found his again, "you'll always be Eren Yeager. No matter what happens to your physical body, you'll always have that stupid, reckless, caring heart of yours." Eren sniffed and looked away, he dropped the severed arm to the floor, eyes filling up with tears once again. "What if I don't want it? Captain," Levi waited. It seemed as if Eren had something important to say. "I think I have to do something... something really bad. I think it's the only way to protect... the people I care about." His face was tense now like he had admitted to a terrible secret. Levi's brow furrowed in confusion. "Whatever it is I'm sure we can-"

"No. This is... it's bigger than the military, it's bigger than Eldia. It's pre-ordained it's... fate." He whispered the last word like it was just for him. Then Eren laughed, a wet, tear-filled laugh that had Levi's blood running cold. "I never even got to tell you... well, it doesn't matter now."

Levi's eyebrows lifted, now he was more confused than ever. "Tell me what?" he kneeled down now, they were almost at eye level, Levi could feel his heart beating out of his chest as he moved his hand down to clasp Eren's. The young man's tears had mostly dried, his nose was slightly red from sniffling and his hair fell gently into his bright green eyes. Levi squeezed his hand reassuringly. The gesture must have worked because soon Eren was sucking in a breath, to steady himself. Levi wondered what else the young man could possibly have to confess. Suddenly his eyes shut delicately and he was moving towards Levi's face. The older man couldn't move away if he had wanted to, his whole body frozen in surprise and fear. Until gentle, chapped lips came to rest on his in an incredibly soft kiss. It lasted all but a second before Eren was moving away again, a soft blush creeping onto his cheeks. When Levi felt him moving his hand out from between his own, he snapped back to reality. He gripped the shifter's wrist tightly, stilling him. He pulled Eren against him, slightly too eagerly, knocking his knees into Levi's chest awkwardly. But the Captain didn't care, because he finally had Eren's lips on his own. The kiss started out intense, both men releasing a flurry of want they had been keeping for too long, but soon it became more. Levi poured all of his emotions into the kiss, and soon it became slower, softer, comforting. They pulled apart panting slightly and looking into each other's eyes as if they were seeing each other for the first time. "Eren whatever you end up doing, just do it on your own terms, and have no regrets." he said finally. He looked into the brat's eyes, and he finally understood something. He had been very wrong about Eren's feelings, he understood that now. He also understood that whatever Eren felt compelled to do was nothing good. But in that moment all he could think about was the guilt he already saw in Eren's eyes. He saw a soft smile tug at Eren's lips, it didn't look forced this time.

"Okay, Captain."