The walls of the abandoned mine shaft reflected the torchlight in distorted patterns. Moss clinging to the gray stone, damp soil beneath their feet—everything pressed down with a suffocating weight in the stale air. Sixty kilometers north of Lostclare, in the depths beneath the abandoned village of Corvoshutain—deeper still into the tunnels that had once served as an eastern outpost for the Hollow Clockwork. The surface base had been seized in the last assault, but the passage leading to the deepest level remained untouched. The report that arrived from Helda Brunn last night contained a single, simple line. "There's still something deeper inside." —And so the three of them were here now. "It's cramped," Sheryl muttered at Leon's back as he walked ahead. The corridor was so narrow that her lustrous mahogany-colored long waves threatened to catch on the mine walls. The sweet scent of fragrant wood hung thick and strange in this sealed space, and Leon's head unconsciously turned toward it. "If you're complaining, you can wait at the exit," Leon said. "I'm not complaining. I'm just stating facts," Sheryl replied. Luna listened to their exchange in silence, her hand resting on her sword hilt. Her pale violet eyes quietly read the darkness ahead. The silver tattoo-like marking on her left cheek glimmered as it caught the torchlight. Leon checked the sensation in his left hand. Beneath the glove, deep in his skin, there was a gradual warmth. (It's rising again.) The Sacrifice Mark—the forbidden ritual burned into him in the Silent Cathedral. Each use consumed his lifespan, drawing forth the power of his prime in exchange for amplifying combat impulses and one other kind of impulse. Over these past few days of control practice, he'd made slight improvements in managing its activation. But he still hadn't grasped how to handle the heat that rose unbidden. A faint vibration came from deeper within. The sound of footsteps on stone. Multiple. "They're coming," Luna said. Her sword was drawn in the same breath. The scrape of metal echoed through the shaft. Sheryl's hand quickly dove into the pouch at her waist, her fingers confirming the aromatic powder. She was checking the remaining amount—Leon understood that much. The Shells had come. The operational units of the Hollow Clockwork—enhanced mages who had carved ancient rituals into their bodies, partially mineralizing their flesh. Their skin, partially covered in gray crystal, gleamed ominously in the torchlight. Five of them. A vanguard, probably. The narrow shaft made side-by-side formation impossible, so they advanced in a column. The problem was the corridor's narrowness. Luna couldn't swing her sword freely. "Tch—" Luna grunted. The moment one of the Shells closed to point-blank range, Luna's body reflexively shifted sideways. Against the wall. Pressed to a distance where Leon's arm might touch her, Luna met the blade in a grapple-like close-quarters exchange, pushing back with the hilt and her arm rather than the blade itself. Behind them, Sheryl attempted an incantation. "—No, it won't work. The stone walls are disrupting the resonance," Sheryl said. The calming barrier normally had an effective radius of about five meters. But in this shaft, the stone walls scattered the magical wavelengths, destabilizing the ritual. Something rare crossed Sheryl's face—something like panic. Luna was being pushed back in front. Leon made his decision. He tore off his left glove. "Fall back a little," Leon said in a low voice. The moment the words left his mouth, he deliberately opened the Mark. Azure flame spilled from the back of his hand. He had no intention of controlling it. At least not in that first instant. Pale blue light raced across the stone walls, and the Shells flinched and retreated. In that one second of opening, Luna threw herself sideways and Sheryl pressed against the wall. Leon pushed the flame forward—just a threat. If he actually burned them, the shaft would collapse. The lead Shell cried out, pulling the rear ranks with it as they withdrew. "...We drove them back," Luna said, catching her breath. A thin sheen of sweat covered her forehead. Yet her eyes didn't waver. Her pale violet gaze quickly confirmed Leon's left hand. "Leon, the Mark—" Luna asked. "It's fine. Still—" Leon began. Then he stopped. No. It wasn't fine. The Mark wouldn't close. It remained open, heat spreading slowly and continuously. He pulled at the reins of control, but they wouldn't respond. Azure light crawled from the back of his hand up toward his elbow, casting pale blue shadows on the stone walls. (This is bad. The threshold—) "Sheryl," Leon called out. She was already moving before he finished speaking. She slipped behind him, wrapping both arms around from behind, placing her hands on his chest. "I'm almost out of catalyst. So—I'll touch you directly," she whispered, her voice barely audible against his ear. Her breath grazed his neck. Leon's body went rigid for a moment. Sheryl's incantation began. A calming barrier—a ritual to suppress rampaging magical power from the outside. With the aromatic powder nearly depleted, direct contact was necessary to maximize the catalyst's effect. The logic of the ritual was sound. Leon understood that. He understood it, but— But Sheryl's hands were slowly increasing their pressure against his chest. The warmth of her body against his back. The vibration of her voice transmitted through his neck as a physical sensation. The heat of the Mark began to recede. Yet simultaneously, there was another heat. Unrelated to the Mark—a simpler, more primal kind. "...Ah," Sheryl's voice faltered slightly in her incantation. Leon realized it. Sheryl's own breathing was becoming ragged. This distance—perhaps it wasn't a distance where she could remain composed either. If she was hiding something beneath that worldly smile. If that question Luna had posed that night—"Did you really just want to test the calming effect?"—now returned with different weight. At a slight distance away. Luna couldn't move. Her sword sheathed, her back pressed slightly against the wall, she watched the two of them. Her pale violet eyes had lost their usual composure. It was that particular expression Luna wore when she was watching something intently—the face of someone "swallowing" something. Except this time, she couldn't quite swallow it. Her fingertips trembled. (Ah.) Luna had realized it. The complicated feelings toward Sheryl—and her own feelings toward Leon—all at once, in this moment. It was jealousy. It might take Luna a little longer to admit that to herself. But here in this dark shaft, watching the torchlight melt Sheryl and Leon's shadows into one, the wringing sensation born in the center of her chest was nothing but jealousy. The incantation reached its completion. The azure light receded, smoothly. The Mark grew calm. Quietly. Completely. Sheryl's hands remained on Leon's chest for a moment after the incantation ended, unmoving. The ritual was complete. The spell was finished. Yet she didn't pull away. Realizing this, Leon slowly moved his right hand. He gently placed it over Sheryl's. Sheryl's breathing caught slightly. Whether it was gratitude or something else entirely—even Leon couldn't say. He simply placed his hand there. That was all. The three of them remained still for a while. Deep in the shaft, the Shells had completely withdrawn. Their receding footsteps were absorbed by the stone walls and faded away. Sheryl withdrew her hand first. Slowly, gracefully. There was no trace of her usual banter. Luna released her grip on the sword hilt. She was aware of the tremor in her fingertips. Leon slowly turned around. He looked at both their faces in turn. He said nothing. There were no words for this moment. --- The three of them walked in silence until they reached the mine's exit. The air was different from before. Physically, too—as they approached the exit, the stone's oppressive weight thinned, and night wind began to flow in. But it was more than that. Sheryl continued walking forward, which was unusual for her. Normally, in a moment like this, she'd say something. A quip or two, delivered smoothly to lighten the heavy atmosphere. That was how Sheryl was. But tonight, there was nothing. Luna's fingertips still trembled faintly. Leon gripped his left hand's Mark through the glove. It was calm. Sheryl's ritual had worked properly. But the Mark being silent and something within Leon being silent were two different matters. Night wind blew from the exit. When the cold breeze caressed his neck, Leon finally felt his head clear just a little. "...I'll compile the report for Helda," Leon said. That was all. Sheryl paused for a beat before responding quietly, "All right." Luna said nothing. The three of them began walking back toward Lostclare. Only the sound of insects filled the night mountain path. The torch flame swayed in the wind. The crunch of gravel beneath their feet—three sets of footsteps—marked out a steady rhythm. Leon found himself thinking. Helda had said there was "still something deeper inside." They hadn't confirmed that today. The Shells' retreat was only temporary. In the deepest part of the shaft—in the section still unexplored—something definitely remained. The mystery of the Mark. The depths of that shaft. Neither was finished.