He wondered if he should have doubted.
He remembered Petra when she had been young and scared, when her hope in dire situations was a hindrance and not a blessing. He remembered her relentless courage, despite how, at the beginning, her blades would shake and her maneuver gear would fail to respond under jittering fingers. He could remember expeditions where she would fumble and drop smoke flares, when he would know, had he looked back, the fear that whited her knuckles around her horse's reigns, that widened her eyes and set her jaw. Had he looked back.
Levi had allowed Eren to make his own choices. It was all about choices, and regardless of action, it was never certain what would turn out to be right or wrong. He had learned, early on, that waiting, that trying to decide, could cost lives. Risks had to be taken and fear over came and even faced, and nothing was ever promised. In his darkest moments, when he realized this was not a war to be won but to die in, Petra's voice would echo in his mind, a sliver of hope when he tried to deny it the most.
"You believe in us, don't you?"
He had, in the beginning. He had allowed her words - words she spoke even when he questioned their truth, when the quiver in her tone would contradict what she said - to sink in, to settle and grow. But it had always come back in horrible ways. Levi had never felt a pain like he had when he believed and they lost, when he held hope and it wasn't enough to save members of his trainee squad. He lacked the words to express the knife in his stomach, the feeling that dug and made him question. But whereas he was silent she was not, and the horrified screeching, the tears that dotted her face - she felt what he had, and perhaps even more. Her empathy was not a weakness but a strength, because despite the sobs he had grown to ignore, the pale complexion that always came before an expedition, it made her stronger.
So he believed in her, if only in words and not in heart. He had learned that not all things could be hoped for and not everything would turn out as planned, and he had felt enough knives in his stomach and stinging in his eyes to know better. Levi had no reason to have faith or believe, because what he knew was a fact. He had collected the strongest and the bravest soldiers, not out of belief but because they were. He trusted their talent, their intelligence, and, in her case, her empathy. Nothing else was a fact, and not to be believed in.
Levi had never questioned their strength, and perhaps that was a belief in it's own. Somewhere, he had believed they were more than human. He had believed they would prevail, even when the thought never crossed his mind, a wordless hope, a feeling he had ignored and despised for years. He had trained himself to be emotionless and unforgiving, because that was what hurt him the least.
He had believed in them, for more reasons than the facts he had chosen them for. He hadn't realized how much until it was too late to say. He had left them on their own, and maybe he was to blame, because he knew, as a truth, that a team was stronger together than apart. He had believed in them too much and it had gotten them killed, bodies dismembered and misshapen, bloodied and lifeless. It was Petra's body that made him pause, one that had always felt too much and shown too much, love and fear and hope and anger, evident in every action she made.
He knew he would never be as strong as he had been with his team. He closed her eyes and lingered on her bloodied cheek, allowing the breathless pain he had caused himself, before launching back into the trees.