The Survey Corps' base — at the entrance to an underground stone cell.
"Lock… I'm sorry."
Hange's voice was heavy with guilt.
Lock raised his hand, gently stopping her from saying more. His calm eyes met hers, and for a moment, the burden on her shoulders seemed to ease. "I know this wasn't your choice," he said quietly. "And I know it was bound to happen sooner or later. Don't carry the weight of it. This time, I've brought you a new specimen. It's in your lab already—something unusual. Focus on that."
He offered her a reassuring nod before turning and pushing open the thick wooden door. The hinges groaned, and the air inside shifted.
The cell was not the dark pit he had expected. Instead, it was surprisingly bright, a single torch-lit chamber carved carefully into the earth. The space stretched nearly a hundred square meters—one large room fortified with stone and iron. Clearly, it had been built to hold someone too important, or too dangerous, to risk escape.
Erwin must have ordered this built recently, Lock thought as his gaze swept the walls. The reinforced structure, the narrow underground corridors—everything spoke of caution, secrecy, and purpose.
He didn't dwell on it further. Nodding once to the stone-faced guards standing at attention, Lock stepped inside.
At last, his eyes fell upon Ymir and Petra.
Ymir sat with deceptive ease, her posture relaxed, her eyes sharp and unflinching. Petra, by contrast, seemed tense, her hands clenched against her knees, her entire body betraying unease.
The sound of Lock's boots on stone made them both look up sharply. The moment Petra saw him, she sprang to her feet.
"Lock! You're finally back. Please, Ymir doesn't belong here—she isn't a threat. She shouldn't be treated like this!"
Her words tumbled out in a rush, her worry plain.
Lock's gaze steadied her, calm but unyielding. "Petra, take a breath. Settle yourself."
He stepped closer to Ymir, studying her carefully. His voice lowered. "Why did you choose me?"
Ymir rose, meeting his stare without flinching. Her answer came firm, each word deliberate. "Because I trust you. My gut tells me you've already figured out who I am, but you've done nothing. That means you see value in me. You know I can be useful."
Lock's lips curved faintly. "Then… are you willing to work with me?"
Her eyes narrowed slightly. "Work with you?" she repeated, stressing the word.
Lock only nodded. He stood there without his gear, completely exposed, yet calm as though nothing could touch him.
Petra's eyes widened at their exchange. "Lock… Ymir… what are you—"
"Petra, leave us," Lock and Ymir said at the same time.
The synchronicity made both of them glance at each other, a flicker of awkwardness breaking the tension.
"You…" Petra's voice cracked. A strange hollowness spread through her chest as she looked at them. It was a feeling she hadn't expected—like watching something precious being taken away. She bit her lip, but in the end, she obeyed. With one last glance, she stepped out, leaving the chamber to the two of them.
The heavy door shut.
For several moments, silence hung between Lock and Ymir, broken only when she finally spoke, unable to contain herself.
"You know more than you should. Far more."
Lock's eyes did not waver. "There's no need for games. I know enough. And yes—I know you carry blood from outside the Walls. But I'm not from there myself."
Ymir froze. Her composure faltered, a flicker of surprise flashing across her face. "You… shouldn't know that. No one here should."
Lock's calm expression remained unchanged, his voice measured. "Then call it a guess. Will you believe me?"
Her instinct screamed to deny it, to push back against his certainty. But his eyes—steady, relentless—made the words stick in her throat. After a moment, she exhaled and nodded slowly. "I can only choose to believe."
Lock's gaze sharpened. "You're clever. So I'll ask again. Will you work with me?"
The question lingered. Ymir lowered her eyes, sinking into silence.
Lock didn't press. He stood in stillness, waiting. He knew what she was weighing. Ymir was not someone who trusted easily—her world had been built on betrayal and survival. And yet, in this place, she had almost no one. Petra, perhaps. And Lock, barely. Beyond that, nothing.
It wasn't trust she considered—it wasa necessity.
Minutes stretched, the silence thick. Finally, Ymir raised her head, her voice low but firm. "I'll agree. But on one condition. Petra comes with me. I only trust her."
"Of course," Lock said without hesitation. "Petra is part of my squad."
He extended his right hand, a faint smile softening his features. "Then… welcome to my team, Ymir."
(Ymir's acceptance carried a weight beyond her words. Even Levi, had he been present, might have muttered in irritation at Lock's audacity.)
Ymir's eyes searched his for a beat longer before she clasped his hand. Her palm was cold, but her grip was steady. "I hope this isn't a mistake," she said.
"Trust me. You won't be in danger here," Lock promised. His expression turned grave. "Not while you're with me. I'll stake my life on it."
Her eyes narrowed. "That's a bold guarantee."
"And a true one," Lock said firmly.
Ymir studied him for a moment more, then finally let go. "Then… I'll believe you. For now."
Lock gave a single nod and turned toward the door. "Come on. You don't belong down here."
Ymir followed closely, her eyes lingering on his back. For the first time in years, a faint smile ghosted across her lips. Maybe following this one won't be such a bad thing after all.
The knot in her chest loosened. Her secret remained unspoken, but for now, her identity—and her life—felt a little safer.
When they reached the door, the guard shifted uneasily, glancing at Ymir and then back to Lock.
"Captain Lock, this doesn't seem…"
"I'm acting on Commander Erwin's orders," Lock interrupted bluntly. His tone left no room for argument.
The guard straightened, stiff as a board. "Understood."
And with that, Ymir stepped back into the sunlight.
The warmth struck her face, and she drew a deep breath. The air aboveground felt different—open, alive. Freedom, fragile though it was, wrapped around her shoulders like a cloak.
"Lock, is Ymir alright?" Petra hurried to her side, eyes searching both their faces.
"She's fine," Lock said simply. "But she'll be coming with me from now on. There's something important she has to do."
Petra frowned. "What do you mean?"
Lock's gaze flickered with something unreadable. "Transform."
"Transform—what?!" Petra's eyes widened, utterly confused.
Ymir gave a small, wry smile at his bluntness. "You're in such a hurry, Captain."
Her tone was teasing, but beneath it lay the weight of unspoken truths, the kind that would soon shake everything.
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A/N: Tell me from what chapter the quality drop i'll rework on them as I mass released too many chapter at a single time that's why I didn't got time to rego through all, and i'm working on like 5 fanfics with every single one daily updates with patreon updates so, please consider my position too, still I will try my best to rework again on this story :)