It was never the pain, or the memories, that kept her up at night. It was always the hunger.
It hadn't always been there; she remembered the times when the only things attempting to keep her up at night was the commotion of the outside world and her own questioning thoughts of morality - two things she had become exceptionally adept at tuning out. This hunger though was a lust so strong that even she was incapable of giving it the cold shoulder.
It wasn't a craving that she could fill with food, for if that were the issue then she would have fixed it by now. Instead, she had come to realize that this starvation was something that lived with her, feeding off her daily interactions. It had been haunting her for years, since the moment she had awoken and returned to this world; since the moment she had been reunited with the one that was responsible for both her isolation and her liberation. He was also the one responsible for the hunger.
But even though he was the cause, he was not the origin.
As a titan, her body was different. Her body had taken on many forms in her lifetime; the form of a child, the form of a teen, and finally the form of an adult. Not everyone made it to that final stage, something she had witnessed many times. However, unlike most humans, she had taken on an additional form, one that she had never wanted to be a part of her. It was this form that brought with it the hunger.
The biggest difference with her titan form wasn't her body, or even her strength. It was her mind. She didn't know what it was like for the others, had never bothered to ask while it was still possible, but in those moments it was as if every emotion she had bottled up in her life was able to set itself free. Her mind would run abuzz with the humming of thoughts, and the hunger was a part of it, speaking a volume above all the rest. It was a pit in her stomach, constantly demanding to be filled; and a voice in her mind, telling her that it yearned to see the pain of their faces, to hear the sounds of their screams.
But most of all, it wanted her to eat.
She supposed this hunger was the same as what the non-sentient titans felt; a driving urge to just devour. Or perhaps, they were sentient, but this hunger was just too overwhelming to resist. There had been times when Annie felt that it was too, and at least one time where it had been. Her existence as a shifter was a testament to that.
If there were any memories that she wished to forget, it was her own thoughts during those moments.
It was now though, as she laid beside the man who had once been her enemy, that the hunger came to her while in her human form. Its voice spoke to her as before, louder than the thoughts of her own mind. It wanted her to devour what was in front of her, to grab onto the blond in front of her and taste his skin, to dig her teeth in and feel the warmth of his body. It spoke to her, showing her the image of the boy she had spared on that day, with the red that recoloured his face until he was almost indiscernible from the bodies that scattered the surrounding fields.
At first she had thought that perhaps it was just her proximity to another human being that caused this, perhaps she would be like this with any other human and that it was just her own mind's way of once again telling her that she was meant to be alone. She had done it consciously so many times that it seemed logical to think that it would do it on its own. She knew now though that this was not true; that the hunger specifically wanted him. She had resisted the urge back then, gone against her natural instinct to kill him. The hunger came back to her now, serving to remind her of where she had failed; of the one human that she had willingly left alive. It was telling her that this wasn't how she was supposed to live. She was meant to be the predator and he was the prey.
She had always liked to think of the titan part of herself as separate from the human side, a way of keeping herself sane during the years of training; of hearing people yell death to the titans. Now though, as the warmth of his body lulled her senses into a state of half-sleep, while the thoughts in her mind only grew louder, she knew that she would never be completely free of its malignance. It made moments like these the hardest.
She leaned in, and ran her tongue up the back of his neck, ending with a kiss so tender that she was unsure if it originated from affection or absurdity. She at least knew that it came from selfishness; she only did it because it helped to tame her appetite.
"Annie, what's wrong?" The voice called out in a voice that was as soft as her kiss, and Annie realized that she had given herself away.
"Go back to sleep," she monotoned. She didn't need to answer the question. Regardless of what she said he would see through it, so it was better to not answer at all. The foundation of their relationship may have been built with lies, but the walls were made of windows. It was near impossible for either of them to hide anything from each other.
"You can't sleep again?" The words came out low and muffled, a sign that the male speaking them wasn't fully awake. Annie knew these moments were the one exception to that statement, that she could get away with a slight amount of deceit. So she does.
She doesn't tell him that he's the cause of her dreams, the source of her sleepless nights. She does her best to hide it from him; she can't tell him, won't tell him that his life is the cause of it.
So she just stretches the truth, knowing that it's the closest she can get to lying to him.
"No, it's nothing. I'm just... I'm really hungry, that's all."