The scraping of metal against a hard surface was the first sound to reach Kaito's ears. A dull ache radiated from his back up to the base of his neck. He tried to open his eyes, but his eyelids felt like lead.
The scent of the air here no longer carried the smell of oil or the burning engines of the Sector Seven docks. Instead, the air felt damp, smelling of wet earth mingled with the aroma of moss.
Kaito felt something small moving across his chest. He forced himself to move his hand, brushing against familiar, soft hair.
"Hana," Kaito murmured, his voice hoarse.
The little girl immediately lifted her head. Hana's face looked pale under the abysmal lighting. She wasn't crying, but her hands gripped Kaito's shirt so tightly her knuckles were white.
Hana helped her brother sit up, leaning him against a stack of rotting wooden crates.
"Are you okay, Brother?" Hana asked, her voice trembling.
Kaito slowly inspected his body. Aside from a heavy soreness and a few scrapes on his arms, he found no deep wounds. He then looked upward. At an unmeasurable height, there was a small hole of light surrounded by the shadows of buildings. They had fallen a long way from the Sector Seven settlement toward the very foundation of Sora-no-Kuni.
"I'm fine," Kaito answered, trying to catch his breath.
He fumbled at the floor around him until his fingers brushed a cold, hard object. It was the hilt of the broken sword Gendo had given him. The silver light that had radiated from it earlier was now completely extinguished. Now, it had reverted to a piece of dull, unattractive black metal. Kaito grabbed the object and tucked it back into his pocket with a swift motion.
"Where are we?" Hana whispered, looking into the darkness ahead of them.
Kaito stood up, bracing himself against the wooden crate. His legs felt slightly weak, but he forced himself to stand tall. He pulled a small lighter from his trouser pocket and flicked it on. The tiny flame illuminated the surrounding area for about two meters.
They were in a vast corridor made of massive stone blocks and giant, rusted copper pipes. This was part of the underground infrastructure usually visited only by senior technicians or left entirely derelict.
"It looks like an old drainage route," Kaito said, beginning to step forward slowly.
Hana walked close by Kaito's side. Their footsteps created long echoes in the silent corridor. Kaito kept his eyes on the stone walls. He searched for signs of emergency ladders or access doors to the upper floors. However, all he found were walls covered in salt crust and water dripping from the gaps between pipes.
After walking for several minutes, Kaito stopped in his tracks. He heard another sound in the distance. It wasn't the sound of dripping water or the echo of their footsteps. It sounded like something hard scraping against the stone floor. The sound repeated rhythmically.
Sreg. Sreg. Sreg
Kaito immediately extinguished the flame in his hand. Total darkness enveloped them instantly. He pressed a finger to his lips, signaling Hana to stay silent. They both crouched behind a copper pipe that ran along the wall.
From the darkness at the end of the corridor, a pair of dim red lights emerged. The lights moved closer, positioned low to the floor. Soon, Kaito could see the silhouette of a creature moving on four legs. Its body resembled a large dog but was entirely hairless. Its skin was a pale, slick grey.
"An Umbra," Kaito thought, holding his breath.
He had heard stories from miners about creatures that lived in the subterranean darkness. They were entities attracted to Aethel energy. Kaito remembered the great burst of light from his sword earlier. He realized that the energy explosion might have lured the creature to their landing site.
The creature stopped exactly where Kaito and Hana had been standing. It sniffed the stone floor with heavy, labored breaths. The red light from its eyes glowed brighter as it found the heat signatures left by their bodies.
Hana covered her mouth with both hands. Her body trembled so violently that she bumped against the copper pipe. The pipe emitted a faint, metallic ring.
But for the creature in the middle of the corridor, that sound was more than enough. The creature immediately turned toward the copper pipe where Kaito was hiding. It let out a low hiss from a mouth filled with rows of razor-sharp teeth.
Kaito knew they couldn't stay hidden. He reached into his pocket and gripped the broken sword hilt again. He tried to focus his mind as he had done at home. He wanted that energy to reappear. He wanted to protect Hana.
But the hilt remained cold. No flow of grey energy appeared. No silver light illuminated the corridor. Kaito exerted all his concentration until his head throbbed, but the object remained dead metal in his hand.
"Come on, work," Kaito whispered desperately.
The creature began to crawl forward slowly. It didn't pounce immediately, instead circling to hem in its prey. Kaito stood up and pushed Hana behind him. He held the broken hilt with both hands as if holding a complete sword.
"Hana, when I move, run in the opposite direction," Kaito said, never taking his eyes off the creature.
"But what about you, Brother?" Hana asked in a stifled voice.
"Just do it!" Kaito snapped.
The creature suddenly lunged with startling speed. Kaito swung the hilt reflexively. Even without a blade, the swing managed to strike the side of the creature's head. The beast was thrown aside, crashing hard against the stone wall.
Kaito was startled by the strength of his own strike. His hands felt tingly after the contact. He realized that even without a physical blade, a residual, highly dense energy still enveloped the hilt.
The creature rose again quickly. It looked angrier now. The wound on its head leaked a thick, foul-smelling black fluid. It opened its mouth wide, bracing for a second leap.
Before the creature could move, a bright blue light suddenly shot from behind Kaito. The light took the shape of a sharp arrow, whistling through the air. The arrow of light struck the creature squarely in the center of its body.
The creature let out a high-pitched shriek before its body began to disintegrate into shards of black ash that vanished into the air.
Kaito turned toward the source of the light. He saw a girl standing in the doorway of a small iron door hidden behind the pipes. She wore a pristine Tenjin Academy uniform. Her long black hair was tied high, and she held a bow made of pure blue light.
The girl lowered her bow. The blue light slowly faded until it vanished completely. She walked toward Kaito with a calm, authoritative stride. Her clear blue eyes looked at Kaito and Hana in turn with an unreadable expression.
"The lower sector is no place for scavenger children to wander in the middle of the night," the girl said. Her voice was cold, yet polite.
Kaito lowered his sword hilt slightly. "I'm sorry, we fell from above. There were officers chasing us."
The girl looked toward the hole far above, then back at Kaito. Her gaze then settled on the black hilt in Kaito's hand. She remained silent for a moment, narrowing her eyes.
"What is your name?" she asked.
"Kaito. Kaito Izanagi," Kaito replied, straightening his dirty clothes.
The girl nodded slowly. "I am Airi Himari of the Himari family. You should come with me before other creatures arrive, drawn by the residual energy you just released."
Kaito hesitated for a second. He knew the Himari name; they were one of the most prominent noble families in Aetheria. Meeting a member of their house in a place like this was extraordinary. However, given their current situation, he didn't have many choices.
Airi turned and walked toward the small iron door she had emerged from. Kaito pulled Hana's hand to follow her. As they passed through the door, Kaito realized they weren't entering another drainage tunnel. Behind the door lay a vast room filled with crystal monitors and sophisticated monitoring equipment.
In the center of the room sat a man in formal attire, busy writing on a large map. The man looked up as he heard their footsteps.
"You brought guests, Airi?" the man asked without pausing his writing.
"Yes. I brought someone who can resonate Aethel frequencies in a derelict sector without having an active mark on his body, Uncle," Airi answered, standing beside the man's desk.
The man stopped writing. He set his pen down and stared at Kaito with deep interest. Kaito felt as if the man were dissecting his thoughts with just a look.
"Interesting," the man murmured. He rose from his chair and walked toward Kaito. "May I see what you are holding in your hand, boy?"
Kaito gripped the broken hilt tighter. He felt a strong urge to refuse, but a sense of curiosity began to grow within him. The man smiled slightly at Kaito's wary stance.
"Don't be afraid. I only wish to confirm something regarding a history that was supposed to be buried," the man said, his tone far more serious than before.
Kaito slowly reached out his hand and showed the black hilt.
Just as the man's hand was about to touch the dull metal, every crystal monitor in the room suddenly flashed red in unison. An alarm blared—a low tone that vibrated through the walls of the building.
Airi immediately drew her light bow again. Her previously calm face was now filled with tension. The man in front of Kaito turned instantly toward one of the large screens showing the map of Sector Seven above.
"They are already here," the man said in a near whisper.
Kaito looked at the screen. Dozens of red dots were visible, moving rapidly from the Sector Seven settlement toward the hole he had fallen through. In the center of those red dots was one large black point, radiating an aura unlike the others.
"Who are they?" Kaito asked, his heart hammering.
The man looked at Kaito with a profound gaze. "The people who will kill you simply because you hold that object."
The sound of a massive explosion echoed from the corridor they had just left. The vibration caused dust to fall from the ceiling. Airi watched the iron door, poised, while Kaito felt the hilt of his sword pulse with heat against his palm once more. This time, the pulse felt like a warning of a danger far greater than the dog-like creature they had faced before.