Kai walked slowly down the hallway, feeling the floor pulsing beneath his feet as if it had a life of its own. The cold from the stone mixed with the strange heat rising from his core, that iridescent light crossing his skin every time his heart beat faster. For a few seconds, he stood still, trying to understand if that body was still really his or if he had already passed the point of no return. It felt like wearing clothes that didn't fit, too big and, at the same time, too tight in all the wrong places.
The shadow behind him rippled, stuck to his own steps, imitating every movement, as if it was waiting for an order. Kai didn't dare speak to Zero right away. The last phrase still echoed in his mind: "Immediate relocation suggested. Patterns of hostile activity detected in adjacent sectors." The fear was almost physical, a constant pressure on his shoulders, and his survival instinct screamed to keep moving, not to stop, never hesitate. But something made him stay there, staring at the moss-covered wall, trying to understand the almost invisible drawings that glowed and disappeared in the same instant.
He took a deep breath, filling his lungs with air that was humid and full of smells he had never noticed before, old metal, ozone, a bittersweet note of living moss, and that indefinable touch of energy, as if the Nexo itself exhaled a chemical and hostile perfume. Kai closed his eyes for a moment, trying to distinguish between what he truly felt and what was an impression caused by the fusion with Zero. When he opened his eyes again, the walls seemed closer, the corridor smaller, the ceiling lower. The feeling of claustrophobia tightened his chest, but he didn't let panic win.
Suddenly, the sound of something dragging down the corridor ahead broke the silence. It was low, slow, like claws touching rusty metal. Kai crouched without even thinking, feeling his body respond with a new agility, as if he weighed nothing. His heart raced, and Zero whispered deep in his mind, almost calm: "Define objective, Kai Ender. The risk of detection has increased." He bit his lip, hesitating between moving forward or looking for an escape route.
With light steps, he slid close to the wall, his fingers grazing the viscous surface of the moss, his eyes attentive to any movement in the shadows. The corridor seemed to bend at the will of the Nexo, narrowing even more with each meter. By instinct, he touched his core, feeling an immediate response, a flash of hot energy running down his arm to his fingertips. With each step, he tried to control his breathing, counting to four before exhaling, following the tip Zero had given him before.
The noise ahead suddenly stopped. The silence became so heavy that Kai could hear his own blood pounding in his ears. That's when he realized: there was something else there with him. It wasn't just a creature, it was a presence, an intention. The shadow behind him stopped, as if waiting for instructions. Kai risked a whisper, almost voiceless. "Zero, threat location?" No immediate answer came, just a chill running down his spine, followed by a dry warning: "Movement detected on the left. Distance, seven meters."
Kai held his breath, pressing his back against the wall. His hand gripped the knife, but he knew the weapon was almost useless in that environment. What scared him most was the feeling that, even with his strengthened body, he was still vulnerable, too human. For a second, he remembered Lina's face, his sister at home, waiting for him to return, believing nothing could stop him. That memory was what kept him from surrendering to fear.
The wall to the left trembled slightly, a low sound, as if something gigantic was breathing inside, behind the concrete and moss. Kai stood still, trying to figure out if it was just another hallucination induced by Zero or if there really was something moving. The core vibrated hard, almost painfully. "Preparation for escape recommended," said Zero, without emotion. He almost laughed at the absurdity, but he couldn't afford to ignore that advice. He took a step back, ready to run, but the floor sank under his feet with a wet crack.
He almost fell, but managed to regain his balance in time, shifting his weight to the other side. The fissure in the floor opened a little more, releasing a bluish mist, cold as ice, that rose and spread quickly down the corridor. Kai covered his face with his jacket sleeve, feeling his eyes burn. Behind the mist, shadows danced, fast and silent, and only then did he realize he wasn't alone. At least three crawling forms emerged from the darkness, too small for adult monsters, too large for any common animal. Their eyes shone like broken lanterns, and their bodies looked like a blend of flesh, stone, and oxidized metal.
Kai felt the urge to attack, but Zero whispered: "Avoid confrontation. Limited resources. Analyze the environment." He backed up a few steps, his eyes fixed on the creatures, which advanced hesitantly, sniffing the air. For a moment, he thought about using the shadow, he felt the energy bubbling there, ready to respond. But what if he lost control? What if the thing inside him took over everything, leaving him no longer himself? The thought was poison, but there was no choice.
"Now or never," he muttered, and, on impulse, focused all his attention on his own reflection cast on the wall in the blue light of the moss. The shadow seemed to come alive, rippling, growing. Kai slowly stretched out his hand, guiding the movement. The creatures hesitated, sniffing the ground, uncertain. With a quick motion, he cast the shadow over them, like a cloak. He felt a wave of heat and cold at the same time, a sharp pain in his chest, but he endured it. The creatures backed away, making a hoarse, high-pitched sound, as if recognizing something dangerous.
Zero approved with a dry word: "Effective approach. Partial control maintained." Kai gasped, feeling his body tremble. The energy circulated too fast, and every muscle seemed ready to explode. But the immediate danger had passed. The creatures disappeared back into the cracks, and the corridor was empty again, except for the bluish mist, now a little less dense.
The tension didn't subside. Kai moved on, still with his chest tight, trying to ignore the constant tingling in his arms and legs. The fear of losing himself was almost as strong as the fear of dying. At every turn, the Nexo seemed to change, corridors twisting at impossible angles, doors appearing and disappearing, as if the whole place was playing with him. It felt like being inside a living, cruel maze, and that time passed differently in there.
He followed a side corridor, guided by an intuition impossible to explain. The silence was almost absolute, only interrupted by the constant dripping of water and the sound of his own heart beating hard. At one point, he saw a rusty staircase leading to a lower level of the Nexo. He wanted never to go down, but something pushed him forward, maybe the desire to understand how far that fusion with Zero could take him, maybe just the hope of finding a way out or a sign that there was still a world outside waiting for him.
The floor vibrated more intensely with each step, and, down there, the gloom seemed even thicker. Kai went down slowly, the steps creaking under the weight of a body that no longer seemed entirely his own. When he reached the end of the stairs, he found a partially open door, blue light leaking through a crack. He peeked through the gap, his eyes adjusting to the irregular brightness. On the other side, a long hall, full of broken machines and hanging tubes, all covered by a thin layer of dust and moss.
He walked through the door, feeling the environment weighing on his shoulders. The air there was denser, almost suffocating, and the deep hum of the energy stones vibrating in the corners increased his discomfort. Kai walked to the center of the hall, his core pounding hard, the shadow stuck to his feet. At the back of the room, a metal bench held an energy stone bigger than any he had ever seen, glowing in a shade that bordered on violet.
"Zero, analysis?" The answer came immediately, objective. "Energy level above standard. Absorption potential: high. Risks: emotional instability, neural overload." Kai hesitated, looking at the stone. Part of him wanted to touch it, to absorb all that energy and see what he was capable of. Another part just wanted to get out of there, find Lina, go back to normal, if that still existed. The conflict was real, painful, and for the first time, he realized he no longer knew how to separate what was his own desire from what came from the presence inside him.
He stepped forward, feeling his core speed up. "Do I need this?", he asked, but Zero's answer was calculated silence. Kai took a deep breath, stretched his hand toward the stone, but stopped before touching it. The glow increased, and for a moment, everything around seemed to stop, the sound, the air, even the shadow was still. The reflection of his own hand on the polished surface of the crystal showed different eyes, brighter, almost alien.
He withdrew his hand, deciding not to risk everything yet. He needed to better understand the rules of that new body, learn to use that shadow without completely losing himself. The world around him started moving again, the stone's light slowly fading. Kai turned his back, ready to leave the room, but one last question kept pounding in his head: how far was he able to go before he stopped being Kai Ender?
He left through the same door he entered, climbing the stairs again. The exhaustion weighed more on his mind than on his body, but the feeling of changing was impossible to deny. He paused for a moment at the top of the stairs, listening to the Nexo breathing around him. He knew that from then on nothing would be the same, not because of the deformed core, nor the shadow that followed him, but because, for the first time, he didn't feel completely powerless. He had a choice. He was still the owner of his own story, even if he shared the body with an impossible secret.