The pain came again like an explosion. For a moment that felt eternal, Kai was no longer human. He was just light, shadow, and a shattered core, melting and rebuilding at the same time.
New memories started coming in bursts. Images of wars on distant planets, cities collapsing under cracked skies, creatures made of shadow and light dueling among ruins. Sounds of strange languages crossed his mind, some familiar, others just noise, but all loaded with an urgency impossible to explain. Between one scene and another, flashes of eyes, hundreds, thousands of eyes, watching, judging, waiting for something from him.
In the midst of this chaos, a different voice emerged. It wasn't human, cold, precise, mechanical. "Fusion process: initiated. Host: identified. Core: irregular, iridescent, unstable." The voice spread through his mind like an echo, reverberating until it became an intimate whisper. "Complete analysis. Mandatory acceptance. Adaptation in progress."
Kai tried to move, but it was as if his body had ceased to exist. Everything was sensation, pain, and fragments of memories that didn't belong to him. Suddenly, he saw his own face reflected in dozens of shiny surfaces, each showing a different version, child, adult, shadow, monster. The core in his chest pulsed, changing color, expanding until it almost exploded. The pain intensified. Kai thought he would disappear forever, dissolve in the darkness of that chamber without even having time to say goodbye to Lina.
Deep in his mind, another presence revealed itself. It wasn't just a voice, it was something alive, ancient, full of secrets and hunger. "Now we are one, Kai Ender. Synchronizing."
His consciousness returned gradually. First, the cold of the floor, the damp moss sticking to his skin. Then, the taste of blood in his mouth. His heart raced, his hands clenched into weak fists. His eyes burned, and for a second, everything became distorted. Every shadow seemed bigger, the details on the walls danced, alien symbols spun like the gears of a mad clock.
Kai tried to sit up, but his head spun. The core glowed so brightly that he could see the outline of his chest, a light pulsing in shades he had never seen. He looked around, expecting to see some creature, but there was only silence. The laboratory was darker than before, as if all the light had been sucked into him.
"Zero," he murmured, not even knowing where the name came from. The cold voice responded immediately, not through his ears, but inside his mind.
"Present. Vital parameters, stable. Host identified. Synchronization, fifty-six percent."
Kai tried to get up, stumbled, and almost fell. His whole body felt lighter and heavier at the same time, every movement bringing new sensations, strength in his arms, tingling in his legs, a strange heat climbing up his spine. When he touched his chest, he felt his skin vibrating, the core beating like a second heart.
"What... what are you?" he stammered, his voice rough.
"Symbiotic nanomachine. Identification, Zero. Function, adaptation, survival, evolution. You have been chosen, Kai Ender."
Fear rose up like nausea. Kai tried to remember everything he knew about Nexuses, machines, legends, none of it fit that moment. He took a deep breath, feeling his throat burn. The world seemed sharper, the smells more intense, the sounds clearer. He could hear the slow drip of water somewhere distant, the almost imperceptible hum of electricity running through dead wires. He smelled the acid of the moss, the cold sweat running down his back.
"I didn't choose anything," he whispered, but the voice in his head showed no compassion.
"Choices are not relevant. Complete fusion is the only viable alternative. Resistance will cause extreme pain. Accept. Adapt."
Kai squeezed his eyes shut, fighting the urge to scream. The pain began to fade, but in exchange it left a strange emptiness, as if part of him had vanished. Slowly, his mind cleared. The whispers on the walls lessened, but now he heard other types of sounds, deeper, almost subterranean, beats, vibrations, pulses. It was as if the entire Nexus had awakened, sensing his transformation.
He dragged himself to a table, supporting his body on the cold metal. He looked at his own reflection on a rusty surface, pale, sweaty face, eyes shining with a supernatural intensity. For a moment, he thought he saw a shadow behind him, undulating, following his every move.
"Am I going crazy?" he asked softly.
"Negative. Mental processes, altered, but stable. Expected symptoms, hallucinations, increased perception, memory lapses. Secondary symptoms, physical enhancement, access to external data, resonance with the environment."
Kai rubbed his eyes, trying to regain control. His chest hurt, but it wasn't an injury kind of pain. It was a pressure from within, as if something gigantic was trying to get out. The core emitted a strong glow, spreading blue light throughout the room. For a second, symbols on the walls began to align, forming words he almost understood, almost.
The sound of something scratching the ceiling interrupted the trance. Kai crouched, picked up the knife from the floor. His hands trembled less than before. The fear was still there, but now it came with a strange feeling, a certainty that he could do more than before. He heard Zero whisper, as if giving direct orders to his muscles.
"The threat is approaching. I suggest a strategic retreat."
Kai staggered to a fallen bench, looking for cover. The noise on the ceiling stopped, but the lights flickered, and the core reacted, a wave of heat ran through his body, and, instinctively, Kai realized he could feel things beyond his own body. The walls vibrated at a frequency, the floor pulsed. For a moment, he saw shapes in the shadows, figures writhing just out of reach of the light.
"Can you protect me?" he asked Zero.
"I can. With limitations. The symbiosis is not yet complete. Your acceptance is essential for full release of resources."
"What kind of resources?" he asked, swallowing hard.
"Increased strength. Limited regeneration. Manipulation of shadows and absorption of residual energy from the environment. Risks, partial loss of identity, emotional instability, exposure to uncatalogued entities."
Kai shivered. As strange as it was, part of him wanted to test it. He felt the urge to touch the shadows, to absorb the faint light from the moss, to hide in the corners like a predator. But the memory of Lina pulled him back. She needed him. He couldn't give himself up to the unknown.
"If I accept, what happens to me?" he pressed.
"You survive. You evolve. Or you're lost forever."
Silence returned, dense, broken only by Kai's rapid breathing. The smell of oxidized metal filled his nose. Little by little, his body obeyed, his muscles responded, his core stabilized. The lights started flickering slowly, and the danger from the ceiling seemed to recede.
Kai stood up, more confident. The fear was still there, but now there was also a new strength, a sense that, even weak, even broken, he had a chance. The Nexus corridors were still a living maze, but now, with Zero whispering instructions and possibilities, maybe he wasn't completely alone anymore.
"Let's get out of here," he murmured to himself.
"Command accepted. We'll go together, Kai Ender. The process has only begun."
Kai grabbed the energy stones, adjusted the knife at his waist, looked once more into the darkness of the laboratory. From now on, everything would be different. He carried inside him something impossible, dangerous, full of secrets that could eat him alive from the inside. But, at the same time, he carried a spark of hope, a chance to survive, to protect Lina, to defy the fate imposed by a broken core.
As he walked through the door, he felt the shadow behind him move. It wasn't just a reflection, it was something alive, following his every step. Kai took a deep breath, trying to convince himself that he was still himself. But deep down he knew, that was the first night of the rest of his life. And, from then on, he would never walk alone again.