The door closed behind them with a finality that made Isaiah's instincts sharpen. The training room stretched before him—a vast space that defied the modest exterior of the Black Dog Bar. Reinforced walls bore the scars of combat, and various training equipment lined the perimeter. The air itself felt dense, saturated with residual power from countless battles.
Benemune walked to the center of the room, her hips swaying with deliberate grace. She turned to face him, and the playful mask she'd worn throughout their walk slipped away into a serious one.
"Before we begin, Isaiah kun" she said, her voice still carrying that melodic quality but stripped of its teasing edge "Show me your Sacred Gear"
Isaiah raised his right hand. The familiar sensation washed over him as Sword Birth manifested, with him an aura of potential crystallizing around his arm. The air shimmered with latent energy, dimensional fractures appearing and disappearing in microsecond intervals and revealing a sword in his extended arm.
Benemune's eyes narrowed with intense focus. She circled him slowly, studying the manifestation from every angle to examine the core mechanics of his power, to know if it's really Sword Birth or something else entirely.
"Interesting" she murmured, stopping in front of him.
She reached out, taking the sword from him.
"It's definitely Sword Birth, but you have successfully merged both holy and demonic elements.... What surprises me is that your forms only showed traces of Demonic power, not of a holy one. Or is it because you can't simply channel your holy element in your forms?"
Isaiah kept his expression neutral, neither confirming nor denying. The accuracy of her assessment was concerning. Most people who'd seen him fight assumed his abilities were standard Sacred Gear manifestations. She was seeing deeper, recognizing patterns he'd worked hard to obscure.
"Your silence tells me everything I need to know," she said, stepping back. "You're hiding something significant. That's fine—everyone has secrets. But if we're going to train effectively, I need to see what you can actually do"
"With respect, Benemune-san," Isaiah said carefully, "I barely know you. Revealing the full extent of my abilities to someone I met less than an hour ago doesn't seem like a good idea"
Benemune laughed, the sound rich and genuine "If that's the case, then let's start with some basic stuff, so we get comfortable around each other"
She walked to a control panel on the wall, her fingers dancing across the interface. The training room responded immediately—sections of floor sliding away to reveal combat circles, barriers of light springing up to contain potential damage, monitoring systems coming online with soft hums.
"Here's what we're going to do," Benemune said, turning back to face him. "I'm going to attack you to push you. I want to see how you react under pressure, how you adapt, how you use those abilities when you don't have time to think."
Isaiah's expression didn't change as the power difference wasn't as insurmountable as Benemune seemed to think.
She raised her hand, and a spear of light materialized—not the crude weapons most Fallen Angels created, but something refined, elegant, humming with precisely controlled power.
"I'm going to come at you with every bit of my strength" Benemune explained "That should be enough to challenge you without risking actual death. Though, you are warned, I am not as stupid and tactless as Kokabiel"
Isaiah's mind raced through options. He'd fought Cadre-level opponent before and won. But Benemune was right about one thing—Kokabiel had been all aggression and power, easy to predict once you understood his pattern.
"One more thing," Benemune added, her smile turning almost predatory. "No holding back. I want to see what you're really capable of. Use every trick, every technique, every transformation. Surprise me."
She didn't give him time to respond.
The spear blurred forward with speed that made Isaiah's instincts screamed, and he activated Sword Birth fully, the blade materializing in his hand as he twisted aside. The spear grazed his shoulder, cutting through his coat but missing flesh by millimeters.
Benemune was already moving, her form a streak of light as she circled him. Another spear materialized in her other hand, and she attacked from two angles simultaneously—high and low, forcing him to choose which threat to address.
Isaiah didn't waste a moment. He ducked under the high strike while parrying the low one, the impact sending vibrations up his arm despite the reduced strength behind it.
"Now then, let's begin the the real test" Benemune commented.
She accelerated, her attacks becoming a blur of light and precision. Isaiah matched her pace, his awareness tracking the trajectories even as his body moved to intercept. The exchange was fast, brutal, each strike and counter-strike demonstrating combat experience measured in life-or-death encounters.
After a particularly vicious exchange that left shallow cuts on floors and walls. Benemune pulled back, her eyes gleaming with genuine interest.
"Not bad at all. You are pretty strong even without your demonic forms" She twirled her spears lazily "Azazel mentioned you fought Vali Lucifer to death with a demonic form, not the one I saw when you fought with Kokabiel. Show me what you have underneath, Isaiah kun "
Isaiah's expression remained neutral, but asked "That would be escalating beyond a training exercise. I don't think it's a good idea to fight in that form"
"Oh, don't be coy" Benemune smiled, flicking her hair "I read Azazel's full reports. You activated something he called 'Devil Trigger' to match Vali's Juggernaut Drive" She gestured with one spear and chuckled "I've been fighting for millennia, Isaiah. I survived the Great War, battled angels and devils at their peak. I can't miss to see what kind of power pushed one of the strongest White Dragon Emperor to the brink"
Isaiah considered her words carefully. There was genuine professional curiosity there, not just idle interest. And she had a point—if he was going to train properly, holding back would limit what he could learn.
"Very well" Isaiah said "But don't say I didn't warn you"
His demonic energy surged as he released the first seal of holding back. Black and crimson energy erupted around him, the air itself distorting from the pressure. His appearance shifted—his body emanating darkness, dark marks spreading across his skin like demonic tattoos. This was Assault Mode, the transformation he'd borrowed from the concept of overwhelming offense.
Benemune's eyes widened slightly, her combat instincts immediately recognizing the familiar spike in power "Now that's more like it!"
She attacked with renewed intensity, no longer holding back. Her spears multiplied, each one carrying enough power to obliterate buildings. The training room's reinforced barriers flared to life, containing the destruction.
Isaiah met her assault head-on. In Assault Mode, his speed and power had increased exponentially. He created spatial rifts mid-combat, using them not just defensively but offensively—portals that redirected her attacks while simultaneously launching his own strikes from impossible angles.
The exchange was brutal, two high-level combatants testing each other's limits. Benemune's centuries of experience showed in her fluid movements and tactical adaptations. Isaiah's spatial manipulation created a combat environment where conventional physics were merely suggestions.
"Excellent, Isaiah kun!" Benemune laughed, genuine excitement in her voice "Show me your demonic form, that you used against Vali when he went into Juggernaut Drive!"
Isaiah's eyes narrowed. She was right, Assault Mode alone hadn't been enough against Vali's final transformation. He'd needed to push further, to access something deeper.
The air around Isaiah changed. His demonic energy shifted from black-crimson to something darker, more ominous—blue-black power that radiated malevolence and absolute control. His body transformed again, but this time it was layered over Assault Mode rather than replacing it.
His appearance became something between devil and demon, aspects of both transformations merging into a singular, terrifying whole. The demonic marks from Assault Mode spread further, but now they pulsed with blue-black energy. His hair shifted to a stark white, contrasting sharply with the dark power emanating from his form.
A spectral katana materialized in his hand, the blade that could cut through anything, even space itself. Around him, phantom swords began to orbit, each one a manifestation of spatial cutting power.
This was Sin Devil Trigger—the fusion of his demonic nature with the concept of absolute cutting and spatial dominance. And combined with Assault Mode, it created something Benemune had clearly never witnessed before.
The Fallen Angel Cadre stopped mid-attack, her spears dissolving as she simply stared. Her expression cycled through surprise, fascination, and then of pure excitement.
"...."
She breathed, but her smile was growing wider by the second "I've seen countless developments of the sacred gears, witnessed the mightiest devils and angels at their peak during the Great War. But this... this is something else entirely. You're not just transforming—you're combining two different forms of energies that shouldn't be able to coexist"
"It's as if your very existence is a walking contradiction"
The blue-black energy around Isaiah pulsed with barely contained power. Even standing still, the sheer pressure of his demonic energy was causing spatial distortions in the air.
Benemune's eyes were practically glowing with interest now. She walked over to the far side of the training room, where an enormous crystal ore sat embedded in the floor—easily ten feet tall and six feet wide, its surface gleaming with a dull gray sheen.
"This" she said, placing a hand on its surface, "is a Power Measurement Ore. It was created during the Great War to quantify the output of high-level combatants. I want you to channel everything you have right now into this ore. Every ounce of your demonic power. Hold nothing back"
Isaiah looked at the massive crystal, then back at Benemune. "You're certain?"
"Absolutely." Her expression was intense, focused. "I need to know exactly what level you're at. The ore can handle it—it was designed to measure fallen angels power to promote them into Cadre. If it glows completely, then your power is similar to that of Cadre"
Isaiah approached the ore, still in his combined transformation state. He placed his palm against the cool crystal surface, and then opened the floodgates.
Blue-black demonic energy erupted from him in a torrent. The malevolent power poured into the ore, which began to glow with an ominous azure-black light. The glow intensified, spreading throughout the crystal's structure, pulsing in rhythm with Isaiah's heartbeat.
The ore began to crack.
Fractures spread across its surface, spider-webbing outward from where Isaiah's hand touched it. The light within grew brighter, more intense, the crystal structure unable to contain the sheer magnitude of power being channeled through it.
Then the ore shattered.
Fragments exploded outward, dissipating into motes of light before they could strike anything. But the energy didn't stop—it poured out into the training room, up through the reinforced barriers, and into the world beyond.
---
Outside the Black Dog Bar, the afternoon sky suddenly darkened.
The sky above the bar turned pitch black, storm clouds materializing out of nowhere, swirling in a vortex centered directly above the building. The concrete shook and trembled, as if an earthquake was about to make its entrance at any moment.
Passersby stopped in their tracks, staring up at sky in disbelief. Car alarms began wailing, windows rattled in their frames.
Inside the bar, Tobio's head snapped up from the glass he was polishing. His eyes widened as he felt the wave of demonic power washing over the building—no, through the building, emanating from the place below.
"Lavinia" he said
The blonde girl was already on her feet, her gentle expression replaced by an alarmed one "I feel it. That's..." She paused, her eyes widening in worry "That's coming from the training room"
The building shook, bottles rattled on their shelves. The lights flickered.
"Benemune" Tobio said, his voice tight with concern. He was already heading toward the door leading to the training area.
"This is beyond anything I've sensed in such a long time" Lavinia finished, following him. Her hand moved instinctively to her side, where magic staff resided "Not even during Utsusemi incidents have I felt something this malevolent and overwhelming surge of energy"
They rushed through the corridor, the oppressive weight of the demonic energy growing stronger with each step. The walls themselves seemed to pulse with dark light, the building's supernatural reinforcements straining to contain whatever was happening below.
Tobio reached the training room door first, his hand on the handle. He could feel the power radiating from the other side which was massive, controlled, but unmistakably dangerous.
BAM!
The door to the training room burst open.
Tobio entered first, his body already tensed for combat, gray eyes scanning for threats. Lavinia was right behind him, her gentle facade completely gone, replaced by the focused intensity of a Longinus wielder ready to deploy Absolute Demise.
They stopped short at the scene before them.
Isaiah stood in the center of the room, still in his combined transformation state—white hair, blue-black energy radiating from his form, spectral swords orbiting around him. The shattered remains of the measurement ore glittered on the floor like broken stars. And Benemune...
Benemune was laughing.
Not the polite laugh of social interaction, but genuine, unrestrained laughter. Her eyes were bright with excitement, her entire posture radiating pure joy.
"Incredible!" she exclaimed, seemingly oblivious to the destruction around her or the fact that two of her colleagues had just burst in prepared for battle. "Absolutely incredible! Do you understand what you just did, Isaiah? That ore was designed to measure Cadre class fallen angels at their peak. You didn't just max it out. You shattered it completely!"
Both slash dog members' eyes widened as they processed the information. They glanced at the destroyed ore, then at Isaiah, reassessing the young devil entirely, who was no longer the calm and outgoing teen they met a moment ago.
Isaiah allowed his transformation to fade, the blue-black energy dissipating, his appearance returning to normal. The process was controlled, deliberate—the power didn't explode outward or fade chaotically, but simply withdrew back into him as if it had never been released.
The oppressive weight in the air immediately lightened. Outside, the black sky began to clear, storm clouds dissipating as quickly as they'd formed. The trembling earth stilled.
"Benemune san" Tobio said, his voice carefully neutral, "you could have warned us you were planning something like this. The entire area felt like it was under siege"
"Oh, don't be so dramatic, Tobi kun" Benemune waved dismissively, though her smile suggested she knew exactly how concerning the power spike had been. "I had everything under control. Besides, I had no idea Isaiah here had this much power. His reports mentioned he was strong, but this..."
Isaiah remained silent, processing what just happened. Tobio was reassessing him as a potential threat or ally—the instinct of someone who'd spent years navigating dangerous situations. Lavinia seemed more curious than concerned, her analytical mind already trying to understand what she'd witnessed. And Benemune...
Benemune looked like a teacher who'd just discovered a student with far more potential than anyone had suspected.
"I need to recalibrate my entire training approach," Benemune said, more to herself than anyone else. "I was planning to help you refine what you had, push your existing limits. But if you can casually destroy measurement ores designed for Cadre Class entities..." She grinned "We're going to have to help you rise way beyond that"
"Perhaps" Tobio interjected carefully, "we should discuss this after the immediate situation is handled. The power spike you two generated just created a significant supernatural disturbance in the human world"
Lavinia nodded, standing up from her examination of the ore fragments. "Agreed. Though I imagine Azazel-sama will be very interested in today's results!!" She smiled at Isaiah, warm and genuine "You're full of surprises, Isaiah-kun!!!"
Isaiah inclined his head slightly, acknowledging the compliment without commenting on it. His mind was already processing the implications of what just happened. He'd revealed more of his capabilities than he'd intended, demonstrated power levels that would definitely be reported back to Grigori leadership. The question was whether this would create opportunities or complications.
Benemune seemed to read his thoughts. "Don't worry about it, Isaiah kun" she said quietly, though her voice carried a note of reassurance "Azazel already knows you're exceptional—that's why he assigned me to you. What we discovered today just means we can skip the intermediate steps and get to the real training to avoid basic stuffs" Her smile turned sharp again. "And believe me, now that I know what you're capable of, I'm going to help you unlock more of your forms while developing the current ones"
There was a promise in those words and a genuine commitment to helping him grow. Isaiah recognized it for what it was: professional respect between combatants who acknowledged each other's capabilities.
"I look forward to it" Isaiah said, and meant it.
Tobio sighed, running a hand through his black hair. "Right. Well, since the immediate crisis appears to be 'Benemune san discovered her student can casually destroy Azazel creations,' I'm going to go handle the human world responsibilities. Lavinia?"
"I'm coming!" Lavinia said immediately as she gave Isaiah a more warm smile. "We should train together sometime, Isaiah-kun. I'd love to help you understand your sacred gear with my Absolute Demise!!"
As the two Slash Dog members headed back upstairs to deal with the aftermath, Benemune turned to Isaiah with an expression that mixed respect, curiosity, and barely suppressed excitement.
"You and I," she said, "are going to do amazing things together. But first..." She glanced at the destroyed ore, then back at him. "First, you're going to tell me exactly what that combined transformation state is called, how long you can maintain it, and what its limitations are. Because if we're going to train properly, I need to understand the full scope of what I'm working with"
Isaiah considered her request. She'd earned some level of trust today—not complete disclosure, but enough to work with effectively.
"The first form is called Assault Mode" he explained "It emphasizes overwhelming offense and enhanced physical capabilities. The second is Devil Trigger—spatial cutting and dimensional dominance. I've only successfully combined them a handful of times. The energy consumption is massive, and maintaining the fusion requires constant focus."
Benemune nodded, her analytical mind clearly already working through training applications "What's the duration?"
"In the combined state? Maybe ten minutes at full intensity before I start experiencing severe energy depletion. And against Vali's Juggernaut Drive"
Benemune smiled approvingly "Good. That means we have a baseline to work from. If you can defeat a Heavenly Dragon in its strongest form, even briefly, then you're already operating at the level I hoped for." She started walking toward the exit, gesturing for him to follow "Come on. We'll call it for today. I need to file reports and redesign your training regimen. Tomorrow we start pushing you past your current limits. If you can maintain that combined form for ten minutes now, I want to see you hit fifteen by the end of the month"
Isaiah followed her out, his muscles pleasantly tired rather than exhausted, his mind sharp and focused. Today had been revealing in multiple ways—he'd shown more of his power than planned, but in doing so, had gained a training sensei who genuinely understood high-level combat.
As they walked back through the bar—where Tobio was on his phone coordinating with someone about weather anomalies and Lavinia was setting up a perimeter to handle any supernatural disturbance by their new guest—Isaiah couldn't help but feel that this arrangement might actually work out.
. . .
The darkness was absolute.
Euclid Lucifuge strode through the hallway, his footsteps echoing against walls that seemed to swallow sound itself. The corridor stretched endlessly before him, lined with pillars of black stone that pulsed with a faint, malevolent energy. Torches burned with violet flames that cast dancing shadows but provided no warmth—only a sickly illumination that made the darkness seem somehow deeper.
His silver hair fell loosely around his face, and his eyes burned with barely contained fury. The elaborate robes of the Lucifuge clan billowed behind him as he walked, their midnight blue fabric adorned with silver runes that glowed faintly in the oppressive gloom.
Who could be behind all this?
The question gnawed at him with every step. His plans had been meticulous, calculated down to the smallest detail. The peace treaty between the Three Factions and Odin in the Underworld—it was supposed to be the perfect opportunity. Chaos during a moment of supposed unity. Blood spilled on sacred ground. The beginning of a new war that would shatter the fragile peace and restore the glory of the true Devil nobility.
But someone had ruined everything.
The Old Satan Faction—his allies, his tools, his carefully cultivated pawns—wiped out in a single night. Headquarters destroyed. Safe houses obliterated. Seventy percent of their operational forces simply... gone. Erased as if they had never existed. Years of planning, centuries of tradition, reduced to ash and memory.
Euclid's hands clenched into fists, his perfectly manicured nails digging into his palms. The hallway seemed to narrow around him, the walls pressing in with each step.
Was it the Satans?
The thought made his jaw clench. Sirzechs Lucifer, Ajuka Beelzebub, Serafall Leviathan, Falbium Asmodeus—the so-called protectors of the Underworld. They had the power, certainly. They had the motivation to eliminate threats to their precious peace. But this? This level of surgical precision, this complete annihilation without leaving a single trace?
Or was it him?
Isaiah. The anomaly. The hybrid mongrel who had somehow survived his attack at the peace conference. The one who had been asking questions, digging into matters that should have remained buried. Euclid had heard whispers of the boy's unusual abilities, his spatial manipulation, his unnatural combat prowess for someone so young.
Could a mere reincarnated devil have orchestrated something of this magnitude?
The uncertainty was maddening. Euclid Lucifuge was not accustomed to uncertainty. He was a master strategist, a pure-blooded devil of the highest caliber, descendant of one of the most prestigious clans in the Underworld. He did not get caught off guard. He did not have his plans reduced to rubble by unknown factors.
Yet here he was in this forsaken place walking through darkness in the darkness.
The hallway finally opened into a vast chamber that made Euclid stop in his tracks.
The throne room was a cathedral of shadows. The ceiling stretched impossibly high, lost in darkness so complete it seemed to devour reality itself. Massive pillars of obsidian rose from a floor that reflected nothing, creating the unsettling illusion of standing on an abyss. The air was thick with ancient power—not the refined demonic energy of devils, but something older, more primal, more fundamentally wrong.
And at the far end of the chamber, elevated on a dais of black stone, sat a throne.
It was carved from a single piece of dark crystal that seemed to pulse with inner light—or perhaps inner darkness. The throne's back rose in jagged spikes that resembled demon horns, and its armrests were sculpted into the forms of serpents devouring their own tails.
Someone sat upon it, shrouded in shadow.
Euclid's eyes narrowed as he stepped forward, his footsteps ringing out in the oppressive silence. The throne room seemed to amplify every sound, turning his measured stride into thunder that rolled through the vast space.
Then, from above, a voice rang out—smooth as silk, sharp as broken glass, dripping with amusement that made Euclid's blood run cold.
"My, my... why so glum, Euclid? One would think someone had just demolished your entire establishments in a single night"
The mockery in those words was palpable, each syllable carefully crafted to wound. Euclid's head snapped upward, his crimson eyes scanning the shadows above the throne.
There, perched on one of the throne's jagged spikes with impossible casual grace, sat a figure that made Euclid's breath catch despite himself.
The man was dressed in dark armor that seemed to absorb light rather than reflect it, its surface etched with draconic patterns that writhed and shifted as if alive. His build was powerful but lean, radiating the kind of strength that came not from bulk but from absolute mastery of power. Long dark hair framed a face that was almost beautiful in its cruel perfection—sharp features, high cheekbones, and eyes that glowed with an inner fire the color of molten gold.
But it was the aura that truly identified him. Ancient, overwhelming, draconic power that made the air itself feel heavy, as if gravity had intensified in his presence. The kind of power that made devils—even pure-blooded devils like Euclid—remember that there were beings in this world that predated their kind, beings that had been gods and monsters when devils were still crawling out of the primordial darkness.
"You..." Euclid's voice was barely more than a whisper, equal parts disbelief and dawning understanding "Why are you here?!"
The figure's smile widened, revealing teeth that seemed just a touch too sharp to be human. He shifted slightly on his perch, the movement serpentine and predatory, and gestured with one armored hand as if presenting a grand revelation.
"Why am I here?" He laughed, the sound echoing through the chamber like distant thunder. "Oh, Euclid. Still so naive, even after all your scheming trickeries. Still asking the wrong questions"
He rose from his perch in a single fluid motion, dropping down to land on the throne itself with perfect balance, one foot on the armrest, the other on the seat, looking down at Euclid like a king surveying a particularly disappointing subject.
"You were seeking answers to who dared to interfere with your precious plans. Who had the audacity to erase your carefully cultivated pawns from existence" His smile turned cruel "Well, congratulations. You've found him!"
The figure spread his arms wide, the gesture somehow both welcoming and threatening.
Euclid's fists clenched so tightly his nails drew blood from his palms. The crimson drops fell to the black floor and were absorbed instantly, as if the very ground thirsted for violence. His entire body trembled—not with fear, never with fear, but with a rage so pure and overwhelming it threatened to consume him from within.
He raised his head slowly, his eyes blazing with hatred, and forced the name through gritted teeth.
"You thought it was either Satans or the Ouroboros Dragon behind the demise of your subordinates..."
"It was me... Crom Cruach!"
The Evil Dragon's smile was triumphant, terrible, and absolutely merciless. He stood fully now, his presence seeming to fill the entire throne room, making the shadows themselves bow in acknowledgment of his power.
. . .
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