The echo of hammers striking stone was the heartbeat of the Tower of Heaven. To the thousands of slaves trapped inside, that sound was a constant reminder that their time was being stolen.
Yet, inside damp cell number 402 in the Lower Sector, a different kind of heartbeat was growing—the heartbeat of a sharp mind hungry for knowledge.
Ren Chicle was now five years old, but his eyes carried the weight of someone who had lived for decades under the whip.
This morning, before the forced labor bell echoed, Ren was sitting cross-legged on the cold stone floor. In front of him, Nana had scratched rows of numbers and letters using charcoal shards she had smuggled from the communal kitchen.
"Nine times nine, Ren," whispered Nana, her voice hoarse from a persistent cough. "And explain to me what happens if we divide it by three."
Ren did not hesitate for a second. His small fingers, rough from crystal dust, picked up the charcoal.
"Eighty-one, Nana. If divided by three, it goes back to twenty-seven. It's a triple pattern. Just like the arrangement of Ethernano crystals in the main corridor; they grow in a three-way fractal formation."
Nana was stunned. She was just an old slave who had once worked as a maid in a port city long before the Tower of Heaven existed. She had only taught Ren basic arithmetic so that the boy wouldn't be cheated by the foremen during future food rationing.
But Ren didn't just calculate; he analyzed. He saw patterns where others only saw piles of stones.
"How on earth do you know about that crystal formation, child?" Nana asked, her blurred vision locked onto the boy.
"I noticed it when Krov dragged me to the mines yesterday," Ren replied calmly. He wrote down complex mathematical equations that a child his age shouldn't have known. "Every time the crystal glows, its vibration changes according to the amount of heat in the room. If I can calculate the frequency, I can know when the crystal will crack before the miners even strike it."
Nana felt a chill that did not come from the sea air creep up her spine. This wasn't just ordinary intelligence. This was an intellect that transcended normal human limits. In less than a year, Ren had mastered everything Nana could teach: reading literature from torn pages of old books, writing with perfect grammar on stone walls, and math that made Nana's head spin.
The Human Variables
The atmosphere in the lower mining sector that day was extremely tense. Thick fog crept in through the cracks in the tower's foundation where it met the sea. Yet, amidst that despair, Ren began to observe the human variables around him.
There was a man named Vane, a former ship engineer who had lost his arm when he was captured. Vane often worked near Ren, muttering mechanical diagrams he could no longer draw. Then there was Kael, a boy a year older than Ren, who possessed incredible agility in pickpocketing spare guard keys undetected.
One afternoon, during a brief break, Vane approached Ren, who was engrossed in staring at the crystal wall.
"You see the structure, don't you?" Vane asked. "This tower is built on an architectural lie. If they keep stacking Ethernano without pressure release valves, this entire floor will collapse in five years."
Ren turned his head, his eyes flashing. "Seven years, Mr. Vane. If we calculate the rate of corrosion from the seawater on the base foundation. But you're right, the structure is inefficient."
Vane chuckled, a sound rarely heard in this hell. "Nana didn't lie about you. You have a brain that can dissect this world into numbers. Listen, kid... if you want to get out of here, your intelligence is the only weapon they can't confiscate. I have mechanical knowledge, Kael has sleight of hand. If we combine them..."
Ren looked at Kael, who was pretending to sleep in the corner while his hands secretly sharpened a piece of metal. Ren began to understand something: to escape, he needed human 'tools'.
The Lacrima and the Map
That night, in the silence of their cramped cell, Nana decided to do something risky. She took out a small object wrapped in dull silk cloth—the only item she had hidden for thirty years in this tower. It was a small Lacrima that was already cracked, but still held remnants of magical energy.
"Ren, place your hand on this stone," Nana commanded softly.
Ren looked at the stone with curiosity. "It contains energy. I can feel it from here. It feels like... the buzzing of bees inside my ears."
When Ren's fingers touched the cracked surface of the Lacrima, an extraordinary phenomenon occurred. The entire room, usually dark, was suddenly filled with a bright white light.
Nana held her breath. She was no mage, but she had seen many slaves with magical potential taken away to the upper levels to be used as experimental subjects or guards. But what she saw in Ren was different. The energy was not wild; it flowed with sharp precision, as if Ren's intellect was controlling his magic power.
"What do you feel, Ren?"
"I feel... the flow of magic," Ren replied, his eyes closed. "I can see how this energy is structured. It moves very smoothly. If I add magical energy from the outside, its structure will change."
Suddenly, the Lacrima beneath Ren's hand began to shift in shape, its molecules forced to alter by Ren's will, before snapping back to its original form an instant later.
Nana covered her mouth with her hand, tears flowing. "Magic... you can do magic, Ren."
"Is this what will let me see the sun later, Nana?" Ren asked.
"This is the key that will lead you out of here," Nana replied in a trembling voice. "But listen to me, Ren. You must hide this. Never let the guards or the priests of Zeref see what you can do with this energy. If they find out you can manipulate the structure of Ethernano, they will dissect you to find its secrets."
Ren nodded. Survival strategy number one: Never show your ace too soon.
The Plan Takes Shape
Over the following weeks, Ren began to quietly establish connections with Vane and Kael. Under Nana's guidance, who provided emotional protection, Ren used his intellect to help Vane calculate the weak points in the tower's ventilation system.
One night, Kael slipped into Ren's cell. He brought a map scroll he had stolen from the foreman's office. The map was complex, full of secret paths known only to the higher-ups of the R-System.
"I can't read it," Kael whispered, handing the map to Ren. "Too many technical symbols."
Ren scanned the map in just a few seconds. Inside his mind, the two-dimensional map transformed into a rotating three-dimensional model.
"This isn't an ordinary map, Kael. This is a magic formation diagram. Here... at the intersection of Sector 7 and Sector 9, there is a waste disposal vent that isn't heavily guarded because the radiation is too high for normal humans."
"But we can't go through there," Kael said in horror. "The radiation will kill us in minutes."
Ren looked at the object in his hand, the Lacrima glowing brightly. "Perhaps for others, yes. But I am calculating a way to... neutralize it."
Vane, watching from the shadows, gave a faint smile. "This boy is building an escape plan that no one has thought of in thirty years. Nana, you are truly raising a dragon in this rat's nest."
However, Nana saw something worrying. Ren was starting to get too absorbed in his calculations and logic. When talking about the escape, Ren referred to other slaves as "necessary distractions" or "expendable variables."
"Ren," Nana called softly once Kael and Vane had left. "Don't let your intelligence freeze your heart. Vane and Kael are your friends, not just numbers in your plan."
Ren fell silent, staring at the wall full of intricate scribbles. "In this place, Nana, feelings are a burden that slows our steps. If I want to get you out, I have to think coldly."
"If you get out without bringing your humanity, then this Tower still wins the battle over your soul, even if you are already under the sun."
Ren did not reply, but he stored those words in the deepest corner of his memory. He realized that his escape mission was not just about breaking through stone walls, but also about keeping the small fire in his chest from being extinguished by the ice of logic he had built himself.
The chapter closes with Ren sitting upright, his eyes fixed on the map he now knew by heart. Beside him, Nana coughed violently, a sign that their time was running out. Ren clenched his fist. Analysis complete. Planning complete. Now, it was just a matter of waiting for the right moment to conduct a massive reconstruction of their fate.