I thought of this as I listed to Let It Burn by Red. I thought it suited Levi very well. The lyrics to me speak to both sides of Levi - the one who doesn't allow his emotions to show, and the other who is in gut-wrenching pain; which explains the questions he asks himself at the end of the story. Tell me if you don't understand anything, and I will be happy to edit this.

Burn The Human

"What's dead is dead," Levi had said to the young brat – Dieter was his name, and Levi remembered of how the grief-stricken brat had shouted that he wasn't human.

Levi thought about those words. How many times had he heard those words caress other's lips, cadets and other recruits whispering that both the commander of the Survey Corps and his second-in-command had been born without hearts? "How else," one member had whispered; his eyes the same shade of blue as someone from so long ago; but his hair not the right color; too dark, and so wrong, wrong, wrong. One of the first to die in the expedition, his eyes frozen in fear as he was swallowed up by a Titan. "How else," the boy who had whispered to his friend – dead, as well – "can he see so many of us to die, and not feel anything?"

And yet…here Levi was.

The blood splattered around his feet.

The sound of screams only he could hear.

And seeing the flash of memory as he saw the bodies of his comrades. No, not his comrades, Levi thought as he looked down again at the three bodies lying on the ground before him. They were his squad. The elite of the Survey Corps, hand-picked by Humanity's Strongest Soldier, forming a squad closer than the others any of them had served in before. They had not died before his eyes; he found them dead, Gunther hanging by the wires of his 3D Maneuver Gear, Erd, half-eaten with his blood staining on the grass, Aruro lying on the ground with blood bleeding from his mouth, and Petra…

It had happened again. A flash of memory burned his skull, causing him to squeeze his hands so hard he was certain that he broke them. A dark memory in the rain…a severed head of a young girl…an abnormal with red eyes that spat out the body of another, his body half-devoured and intestine poking out of the dead – dead, dead – piece of flesh. Did it truly matter that he did not see their last moments? To see Isabel's head severed from her body, the rest of her body crushed as Farlan was being chewed? Did it truly matter that he did not see of how his squad died, not seeing of the naked fear in their eyes as they faced an enemy that could not be defeated?

"I'll trust you on this one…Erwin."

He had pulled Gunter from the wires that held him and placed him beside a half-devoured Erd. Aruro heavy against his small stature and broken ankle, but still managing to lie him down by his comrades. Levi had closed their eyes. A memory of doing this again – closing another person's eyes; their blood coating their face with mud and dried rain, their hair still damp as the hands they adored – "Aniki! Look, I finally did it!" – closed those green orbs. Isabel…

Levi still remembered Erwin scolding him afterward, telling him it didn't matter what state the body was in when the soldier died. "Do not hold onto things that do not matter, Levi." Did closing Isabel's eyes bring him the closure that he sought, despite the rage and horror that he felt upon his friend's deaths?

Did it now?

Levi stood, a stab of pain surging through his leg at the protest of his ankle. Despite the agonized memories and smell of death and blood almost overpowering his senses, the captain of the Survey Corps walked to the bloodstained tree.

His eyes were as blank as they were when they first saw her body. The blood was slightly drying now, her hair now longer fine to the touch as Levi's gray eyes saw the blood on her face. Her spine was turned, her entire body turned towards the tree, having been stepped on by the Female Titan. The Survey Corps symbol that she dedicated her life to was towards him, slightly catching in the wind that suddenly appeared. Levi's eyes looked towards the blood-stained tree. There was so much. Even if his hands barely brushed the surface of the bark, he was certain that his hand would be stained with Petra's blood. So much… Levi thought, staring at the dead eyes that bored into his own. She was beautiful, even in death. Her copper-red hair tinged a bright orange in the fading sunlight, and her eyes…

Levi had never told her of how he loved her eyes. Golden almost, so bright that Levi had to remind himself that Petra was real. That…what they had was real. Despite the cold mask he kept, the dark-haired man knew what it was like to love. It came in the form of his mother, when he stayed by her bedside until she died. Even now, as he was able to eat two or three meals a day, Levi could still remember the raw pain of starvation, his face becoming thin and his legs and arms losing all of their strength; his eyes sunken. Finding it hard to breathe even as his tiny chest moved and his long hair that his mother once praised and lovingly caressed when he was very small, coming in clumps besides his feet. Knowing, even before the age of ten, that no one wanted to help him. That no one wanted to save him. Even in the Underground, it was considered dirty to be a whore's son.

And the sudden dull acceptance as he almost died, before being saved by a violent man who taught him violence and death, blood, and the need to survive. Isabel and Farlan… Despite of Erwin's words, Levi was certain he would never be able to forgive himself for his friend's deaths. The image of finding Isabel sleeping beside him after a nightmare, and Farlan's sigh of exasperation at the sight of Levi in his "maid outfit" as he dubbed it, haunted him as much as their deaths. It took their deaths to make Levi realize of how much he cared for them. Their names were never to be spoken. It hurt too much physically to even say the names of the girl who considered him her brother, and the young man who thought of him as the only friend he had. Living together…in the hell that they had until they joined the Survey Corps.

Until now, Levi thought that he would never experience more pain and agony than the deaths of Isabel and Farlan, the closest thing to a family he had since his mother had died in the bed he had been born in, dying in a nameless whorehouse. Now the pain came in waves as Levi attempted to touch Petra. His breathing almost stopped, and his eyes blurred at the sudden feeling of queasiness. The small conversations that he had Petra had while the rest of the squad was asleep, remembering the gentle feeling of her hands threading through his hair, the smile – too warm, too blissful – that he saw only when they shared their small moments. Levi could remember of how she had kissed him. The memory of her soft lips on his own almost made him pause and brush his hands over his lips. Farlan would be laughing at him now if he knew. He wouldn't believe that the dark-haired soldier was in love with another. One time, the former thug had stated that relationships were messy and clumsy. Even when he was beyond the Underground, Levi found that this world was cruel as well. And yet, his own words remained empty words as he found himself loving the one person who loved the brokenness of him. Levi could remember the taste of tea on Petra's lips as he leaned in the early mornings to kiss her; her fingers entangled in his hair, the smell of her his in nose as she moved to her other duties as a member of his squad. The sound of her laughter – sounding so much and so different from Isabel's at the same time – as she talked with Gunter and Erd. The small amusement that filled her eyes after she finished explaining the ever-occurring arguments with Aruro. Levi had once read a poem once – some shit Isabel had managed to get her hands on – comparing a lover to a sun, every moment and action feeling like a glow, and a light that would obscure the darkness. The sight of her smile, her eyes half-lidded with bliss as she hummed even the darkest of days, looking so beautiful stained with blood.

Petra…

The Survey Corps member lying dead on his feet had been his sun. Just like the poem that Levi had never thought he could relate to. The image of Petra as the sum – his beautiful, eternal sun – bored into his mind until it hurt. The renewed grief was enough to almost cause him to choke and to collapse on his knees. Never again. Never again would he see her smile. Never again would those eyes light up with bravery and kindness, or feel the warm touch of her fingers across his skin. "Levi…" The sound of his name on his lips, impossibly sweet and burning now as the dark-haired lover crouched down towards Petra.

He held her in his arms. If it wasn't the fact that her spine was crushed and her face was marred with blood with her eyes open, Levi would have thought that she was asleep in his arms. The other part of himself – the one who had screamed, hysterically and shed tears upon the deaths of that rain-soaked day, tearing apart that abnormal that had killed them until there was only a pool of blood; the one that had collapsed on Isabel's bunk after drying the blood from his face and uniform for two days and not moving an inch; the one that had faintly, so faintly, wished to carve up the Female Titan for destroying another part of him – almost came out. But Levi held firm, and instead brushed Petra's dead forehead against his.

There was only the sound of breathing. It echoed inside the forest, driving Levi almost insane as he continued to stay still with Petra lying dead in his arms. This tenderness was not expected of him. Petra was the one that initiated the affection, either from simple warm touches or kisses that sometimes left him breathless. There was only silence. Slowly, Levi closed her eyes. I never told you how I felt. As always, I thought there was more time. Seeing her with the eyes he loved closed did not elevate the agony in his heart.

"I'm sorry," Levi whispered. He didn't know who he was speaking to. Petra, perhaps? His mother, who would be horrified at the kind of man he had become? The two members of his shitty family, who had died not knowing that Levi had cared so much about them?

His squad? "I couldn't be…the person you thought I was."

Again, Levi pressed his forehead against Petra's. I never say what needs to be said.

"I love you," he rasped. It caused an involuntary shudder in his body, admitting the words he never thought he would have the ability to say. "I…loved all of you, Petra." His hand cupped Petra's face, his eyes looking at another person who couldn't not save.

Slowly, his lips captured hers. It was exceedingly gentle, as if she was asleep and about to wake any moment. But, she wouldn't awake. Sharp pain entered Levi's spine, and he willed himself to not let go. I couldn't say those words, or save anyone I cared about…again. Again.

Levi's lips moved away from his lover, staring once more before carrying her in his arms. Again…I made a choice I regretted the most. Although I will tell Eren that no one knows the outcome…

I still…

Petra was still, lying beside her comrades. Levi almost reached out to touch her face again. To touch her one last time. To tell the unsaid words that he had not said when she had been breathing and alive.

Four members of the Survey Corps were standing behind him as Levi stood. Even without looking back, the raven-haired man could tell that they had stretchers and white cloths – to cover the bodies. The other side of him – the cold and heartless side that he kept for humanity – didn't break as he told the soldiers to take the bodies and put them with the rest.

How long… Levi thought as he looked back one last time, his eyes never leaving as Petra's body was rolled away, seeing the hair caress in the wind and the part of her face showing to him as the once living and breathing loved one was abandoned, how long will this part of me last? The one that is hiding, never seen, and always there deep within my heart? Until I cannot stand this pain anymore? Until I cannot hide my true face, and my fears?

Will it burn until there is nothing left?

How long...will it burn until I am truly no longer human without a heart?