He could see it in her eyes from the very first time he saw her. He'd recognized it when the girl had fearlessly met his gaze, her black eyes unconsciously revealing the empty void hiding behind them. He'd immediately known that this girl had gazed into the abyss long enough for the abyss to gaze back into her, and it had left an ugly scar on her soul.

A scar matching his.

"What doesn't kill you makes you stronger" was a favourite saying among the survivors of the Scouting Legion, but both Levi and Mikasa knew the inaccuracy of those words. Sometimes, what doesn't kill you doesn't make you stronger. Sometimes, what doesn't kill you leaves a gaping wound in its stead, a permanent reminder of what you once were.

In his eyes, she could see that gaping wound. A tear in the fabric of his very essence, a damage that could never be undone.

A damage matching hers.

She's just a girl, Levi thought as he watched her majestically soar through the air, using the maneuver gear as if it were an extension of her own body. He had to remind himself over and over that she was just a girl – a very young one, too – and that the angelic wings he kept seeing on her back were nothing more than an illusion of his imagination.
Later that night when he held her body close to him, his hands would linger an extra moment on her shoulder blades, just to make sure.

Eren is the one I truly love, Mikasa thought as she walked through the empty corridors in the middle of the night. She paused for a moment outside Eren's room, but then continued towards the room in the other end of the building – Levi's room. No matter how much she loved Eren, he could never understand her nightmares. He could never comfort her in the middle of the night the way Levi could.
I only love Eren, she reminded herself, curling up next to her corporal. In his bed, she could cry freely without him ever asking any questions. In his arms, she could finally go back to sleep.

It's just physical, Levi thought as he allowed Mikasa to push him against the wall, her inexperienced yet determined lips crashing into his. It doesn't mean anything, he convinced himself as he slipped his tongue inside her mouth.

It's just physical, Mikasa thought when Levi deepened the kiss, grabbing her beloved scarf to pull her closer. It doesn't mean anything, she convinced herself as she allowed him to carry her back to his room.

"I hate you," she moaned as she desperately held on to him, her nails leaving red lines on his naked back.
"No, you don't," he answered, kissing her neck hard enough to leave a mark, branding her as his. "You wish you did, but you don't." Mikasa tried to come up with a response, but was silenced by a pair of lips once again meeting hers.
He was right, of course. She could never hate him, she needed him too much. To meet his gaze, to hear his voice, to feel his callused hands on her naked skin – she craved it all. It was like a part of her had always longed for someone like him, hungered for someone just as damaged as her. Her cravings frightened her, but at least she knew they worked both ways. However addicted she was to him, he was just as addicted to her. She could see it in his dark, calculating eyes, just like she could see the scars on his soul.

To the world, they were perfect. Unbreakable, undefeatable, humanity's strongest soldiers. No one ever saw the deep wounds hidden inside them. No one ever looked close enough.

"Don't ever leave me," Mikasa whispered breathlessly beneath him, still trembling from the aftershocks.
"Never." Leaning on his elbows, Levi rose up and looked her deep in the eye to show her just how much he meant it. He'd finally found a person who not only saw how damaged he actually was, but also understood it. He gingerly touched the scar on the girl's blushed cheek. This strong, beautiful and oh so damaged girl was his now. He kissed her again, this time softer than before. "Never," he repeated. "I'll never let you go."

That's the thing about damaged people – it takes one to know one.