The purple sky of the Underworld was slowly darkening, yielding to the night, but up here, high in the mountains, it was still light. Thick, milky-white steam rose from the cascade of pools, mingling with the cool mountain air and the soft glow of magical lanterns set along the stone ledges. The water, saturated with the very energy of the mountains, was not merely hot—it was alive. It seeped into every pore, driving out the fatigue accumulated over days of training, battles, and sleepless nights.
In the uppermost, most spacious pool, a tense silence reigned. Kiba, citing urgent business, had tactfully withdrawn a few minutes earlier, dragging a staggering Gasper along with him.
Three remained. Azazel, leaning lazily against the stone edge, was still sipping sake from a floating wooden cask with that same crooked smirk. Jin lay completely relaxed, eyes closed, savouring a rare moment of physical peace.
And Issei.
Issei Hyoudou looked like an overripe tomato. He was red. Absolutely all over. From the roots of his hair to the tips of his toes. The heat of the spring, mixed with the pure, unadulterated embarrassment from the recent conversation about his "motivation" and the presence of two beings whose auras pressed down like solid rock, had turned his stay here into an exquisite torture. He was trying to endure. He was desperately trying to prove that he, the future Harem King, could withstand the same temperature as the leader of the Fallen Angels and that insufferable blond.
But his human (albeit demonic) body was surrendering. The heat burrowed down to his very bones, his head spun, and every breath seared his lungs. He cast a martyred look at Jin. Jin was lying as if he intended to stay there for an eternity.
At some point, Issei realized he could take no more. Honor was honor, but he risked being boiled alive.
"...Hot," he croaked, rising to his feet with difficulty and clutching the edge. The water reluctantly released him, streaming down his crimson skin. "Jin, you... are you coming?"
Jin cracked one eye open.
"Nope," he drawled lazily. "I'll stay a while. Just started warming up."
Issei's face twisted into a grimace of despair. He exhaled heavily, feeling his self-esteem plumb the depths of the spring. To the accompaniment of Azazel's amused chuckles, he staggered out of the water and trudged toward the changing room.
When Issei's footsteps faded, silence reigned in the pool once more, broken only by the soft murmur of water trickling over stone and the distant sounds of the Underworld's nightlife. The steam thickened again, veiling them from each other, leaving only two silhouettes in the milky haze.
Jin closed his eyes again. He was alone with Azazel. With the very objective for which he had gotten involved in this trip in the first place.
"A drink?" The leader of the Fallen's voice sounded unexpectedly close.
Jin opened his eyes. Azazel, still wearing that lazy smirk, was indicating the floating tray with his eyes. Two empty porcelain cups stood beside the cask. He nudged the tray across the water toward Jin.
The offer was not merely a gesture of courtesy. It was an invitation to a conversation between equals. Jin considered for a moment, then sat up, drawing closer.
"Why not?"
Azazel took one cup, deftly scooped the warm, fragrant liquid from the cask, and held the tray out to Jin. Jin repeated the gesture. Azazel nodded silently at him, as if proposing a toast, and drained his cup in one gulp. Jin followed suit.
He brought the cup to his lips, inhaling the thick, sweetish aroma with subtle fruity notes. "It's been a while..." drifted an aloof thought through his head—an echo of a past, long-forgotten life where alcohol was a commonplace, not a tactical instrument.
He drank. His mouth was pleasantly seared, and a wave of pure, warming fire rolled down his throat. This heat instantly dissolved throughout his entire body, merging with the external heat of the spring. The effect was astonishing. His already relaxed body sank into a state of absolute comfort, warming from both within and without, while his mind, on the contrary, became crystal clear and sharp. He exhaled steam with a noisy sigh.
"Good stuff."
"A demonic exclusive," Azazel chuckled, refilling both cups. He set his own on the tray and pushed it back toward Jin. "Making peace with Sirzechs was worth it for this alone. Their vintners work miracles."
Jin retrieved his cup and left the tray to drift between them. They drank in silence for several minutes, savouring the moment.
"So, Izayoi Jin," Azazel spoke at last, breaking the silence. His tone was as casual as if they were sitting in a bar, not a hot spring on (conditionally) hostile territory. "How do you find our Underworld? Dragons at the entrance aside. Did you like the purple sky?"
"Too much purple," Jin answered honestly, taking another sip. "And the architecture is ostentatious. But overall, it's livable. At least it's warmer here than in my old apartment."
Azazel laughed.
"Pragmatic. I like it. So the house Sirzechs threw at you suits your taste? The gilded cage not too tight?"
"A cage is a state of mind, not a place of residence," Jin observed philosophically. "As long as it allows me to do what I want, the gold suits me just fine."
"And what do you want, Izayoi Jin?" Azazel's gaze sharpened, grew more penetrating. "You tore Riser apart, scared my old guard half to death, fought the White Dragon, mouthed off to the leaders of the three factions, and now you sit here drinking sake like it's the most natural thing in the world. You must have some goal. Power? Glory? Or are you, like our young friend Issei, simply looking for... inspiration?"
He made a blatant insinuation regarding female charms, awaiting a reaction.
"Issei's motivation is a separate clinical case," Jin replied evenly, ignoring the provocation. "I'm still not convinced that this explosive growth in his power won't end as abruptly as his puberty."
Azazel burst into deafening laughter, nearly spilling his sake.
"Ha! There's something to that! I admit, betting on hormones is a risky venture!" He finished laughing and refilled his cup. "But you're wrong on the main point, Jin. In part, I agree with you. It's primitive. It's vulgar. It's laughably simple."
He took a sip, and his face grew serious for a moment.
"But that's precisely why it works. It's the purest, most unclouded motivation. There's no hidden agenda in it. There are no complex ideals that can be broken or called into question. He's not fighting for 'world peace' or 'justice.' He's fighting for what he considers most precious—Rias Gremory's breasts. And that makes him absolutely sincere. And sincerity is the fuel that Ddraig understands best. You can crush an army, you can shatter faith, but you can't defeat a simple 'I want!' As long as he wants it, he will grow stronger. That is precisely why he is here, while dozens of others, more talented, have long perished."
Jin listened, his head tilted slightly. There was a logic to it. Peculiar, but ironclad.
"Yeah, yeah," he drawled, pretending the topic bored him, though in truth he was merely waiting for the right moment. "The philosophy of perverts is, of course, fascinating... but speaking of systems and motivations..."
He paused, and Azazel immediately leaned forward. He'd taken the bait.
"I recently stumbled upon a certain literary work of yours," Jin continued casually. "'The Sacred Gear System: Analysis, Classification, and Anomalies.' Quite an engaging read."
Azazel's eyes lit up. This was his element. This was what he loved more than women or drink. Research.
"Oh?" he drawled, his voice instantly losing all its languor. "And what did a... specimen like you find in dry theory? Considering that you yourself are a walking anomaly that doesn't fit into that theory in the slightest."
"Precisely why it grabbed me," Jin pulled the floating tray closer and poured sake for them both himself. They shifted imperceptibly closer; the steam around them seemed to grow denser, creating an improvised study. "I was trying to understand the creator's logic. It was God's work, wasn't it? This whole system with artifacts inside human souls."
"Correct. His greatest and, perhaps, most dangerous project," Azazel nodded, completely immersed in the conversation.
"Well then," Jin continued. "The entire system seems brilliant, but it has a fundamental flaw. The binding. You yourself write that the Gear is attached to the soul but manifests through the host's body and emotions. This creates a conflict. The host might be weak. Their body might not endure. Their emotions can lead to self-destruction, like Juggernaut Drive. It's inefficient. It's a crutch."
Azazel stared at him, unblinking. This wasn't just an idle question. This was a systems architect's analysis.
"And you have a better suggestion?" he asked, with irony.
"More of a question," Jin took a sip. They were both slightly tipsy by now, and it was liberating. "Why? Why is a host, a body, this whole biological shell even necessary? Why couldn't the Sacred Gear—Ddraig's or Albion's soul, for instance—be embedded directly into the human soul at the moment of its creation? Not as an 'application,' but as part of the 'operating system'? Integrate them on a fundamental, conceptual level. That would solve all the problems of control, rejection, and physical limits. That would be... ideal."
Azazel froze with his cup halfway to his lips. His drunken smirk slowly drained from his face. He stared at Jin as if the latter had just voiced the most heretical and the most brilliant thought he had heard in the last several millennia. He set the cup on the tray. His gaze sobered in an instant.
"Because that's..." Azazel slowly chose his words, his brain working feverishly. "That's conceptually impossible."
"Why?"
"You don't understand what you're talking about!" Azazel leaned forward, making the water in the pool ripple. "You're not talking about improving the system, you're talking about creating a god! A soul is an absolute. It's a pure concept, the prime foundation. And a Sacred Gear, even a Longinus, is... it's a program. A complex, incredible tool, but still a tool, written in divine code. You cannot inscribe a program into the very essence of the processor that is meant to execute it!"
He gesticulated, splashing sake.
"The system uses the soul as a power source, like a battery! It attaches to it! But it operates through an interface, which is the host's body and consciousness. Attempting to embed Ddraig directly into the soul's architecture..." Azazel rubbed his temples. "It would cause a fundamental paradox. A system attempting to rewrite its own source code in real time. It's like a hammer starting to rebuild the hand that wields it, mid-swing. It... it would lead to collapse. To the annihilation of both the soul and the dragon. God was a genius, but even He couldn't break the fundamental laws that He, perhaps, Himself created. It's... simply impossible."
Jin listened to his impassioned tirade in silence. He understood everything. Impossible. A conceptual limit. His own power, which worked differently, which seemed as if it were part of his soul itself, once again fell outside the general picture.
They sat in silence. Azazel breathed heavily after his lecture. Jin thoughtfully turned the empty cup in his hands. They were both drunk—one on alcohol and excitement, the other on information.
"So... impossible," Jin repeated quietly. "Interesting."
He lifted his gaze to Azazel, and a cold spark gleamed in his eyes—that of a researcher who had found a new, even more complex riddle.
"In that case, Azazel, I have another theory... What if someone already tried to do this—and succeeded?"