The cavern breathed. Not with air — with power. Old power. Primordial, raw, older than devils, older than the Bible, older than the first time Ddraig ever screamed his rage at the sky. The sapphire veins along the walls pulsed slowly, like a colossal, subterranean heartbeat. The mana was thick enough to chew. My skin buzzed, my bones hummed, and my lungs burned in a way that had nothing to do with oxygen and everything to do with being inside the living memory of dragons. I stayed on one knee for a few seconds more, feeling the last phantom bite of Tiamat's breath fade from my nerves. Every inch of me hurt. Not "stubbed toe" hurt, but "stood in front of a tactical nuke and argued" hurt.
[You're still alive.]
'Barely.'
[Barely is more than most. Don't get greedy.]
A low, faintly amused rumble shook the cavern. It wasn't Ddraig. That one came from in front of me.
"On your feet, little spark," a voice said — female, cold, amused, layered with something ancient. "If my flames didn't erase you, groveling won't either."
I sucked in a slow breath, braced my hand on my knee, and pushed myself upright. My legs protested; my spine voiced a formal complaint; my aura flickered like a dying light bulb and then stabilized.
"Give me a second," I muttered. "You're not exactly a campfire."
A low snort echoed, sharp and unimpressed. The glow in the chamber shifted. The massive draconic silhouette coiled in the darkness shifted, contracting — bone, scale, and mana folding in on themselves like a star imploding into a new shape. The ground trembled. Light warped. The pressure in the air eased, then sharpened. Tiamat emerged from the dim like a statue remembering how to move.
This time, she wasn't a 'kilometer' of dragon. She stood on two legs. Humanoid, but only in that approximate way dragons copy things they find amusing. Tall — taller than Kala, just shy of towering — with the posture of a warrior who never needed armor to win a war but wore it anyway. Pale skin faintly illuminated by the blue aura that haloed her, as if her body had decided "daylight" wasn't bright enough. Long hair, flowing in waves down to her thighs, a cool sky-blue that shifted shades like mist over ice. Her eyes were cutting ice-blue, intelligent, predatory. It wasn't human beauty. It was draconic majesty wrapped in a humanoid format: every glance evaluating, every tiny motion controlled, gaze that promised ruin and opportunity in equal measure. Wings unfurled behind her — vast, sweeping, each membrane like midnight silk shot through with shifting ocean colors. They weren't just limbs. They were declarations. Her tail moved in slow, deliberate arcs behind her, covered in layered blue scales and ending in a sleek, fin-like tip that looked elegant right until you imagined it whipping someone's head off. Her clothing resembled divine-era combat gear: a fitted upper layer with gold accents at the collarbone and shoulders, dark bracers shaped from what looked like her own shed scales, and a long, white garment belted at the waist, split at the sides to let her move without restriction. Every piece looked functional and ceremonial at once. Bare feet touched the sapphire stone lightly, the way a storm cloud might "touch" a mountain.
Her build…
Yeah. Calling her "fit" would've been a crime. She had the kind of athletic, sculpted body that screamed power first, beauty second — shoulders defined, arms toned, legs crafted for leaping off mountains, curves that emphasized strength rather than softness. If a goddess of battle decided to cosplay as a dragon, she'd still feel underdressed next to this. Her breasts were huge, but firm, like if they were full of breast milk, and her rear was wide and plump, but toned and perky. Even without her full dragon form, Tiamat radiated sovereignty. Crunching, effortless dominance. Not just a True Dragon — a Dragoness who'd once looked at continents and decided whether they stayed the shape they were. Her eyes narrowed as they fixed on me.
"So," she said, voice chilled steel and wildfire at once. "You finally crawl your way here, little Spark. After your little show with the wannabe Phenex… and your request to me."
Her tone made "request" sound like "idiotic gamble." I stopped five paces away. Any closer without permission felt like suicide by dragon etiquette.
"I'm not Ddraig," I said, calm. "Name's Issei. In case you haven't listened the first time."
Her eyes flicked over me, taking everything in — aura, posture, burns, scars, the way I held her gaze and how my hands didn't shake even though they really wanted to.
"Do not insult me with names," she said. "Your aura is his. Faint, but there."
Her wings twitched once: irritation. "And yet… you speak with confidence." Her lips tilted, almost a smirk. "Interesting."
[Tiamat… it has been a long time.] Ddraig finally rumbled, his voice echoing not just in me, but out — a vibration that made the air itself lean.
Her entire expression snapped. She took one step forward. The cavern shook like it remembered earthquakes.
"You."
[Oh boy.]
Her teeth flashed in a snarl — far too many, far too sharp, even in human shape. "You dare speak in my presence again, you red parasite? After stealing what was mine?"
[Borrowed.] Ddraig coughed. [I borrowed it. And I… forgot to return it.]
I felt Tiamat's killing intent spike. The air tightened around my lungs like a fist.
"'Forgot'?" she hissed. Sapphire flames licked along the walls. "You vanished into battle after battle, leaving my treasure lost to time. You miserable, hoarding lizard."
"Okay," I said, raising a hand. "Time out. If you're going to roast someone, roast him. I'm just the idiot renting out my soul."
Her gaze snapped back to me. The killing intent didn't vanish, but it shifted — focused, evaluating.
"Hmm."
She leaned closer, her shadow swallowing me whole. Her eyes narrowed. Her tail cut a lazy figure-eight behind her, a knife pretending to be calm.
"You are no ordinary host," she murmured. "That much is obvious."
Her gaze swept me again, slower this time.
"Your soul smells of discipline," she said. "Fire tempered by restraint. Rage, strangled on purpose. A dragon's hunger in a human cage." A pause. "But is that enough?"
"Working on it," I said.
She tilted her head. The gesture made her look almost… curious.
"I came here because of your treasure, too," I said.
The temperature in the cavern didn't just drop. It went all the way down. Every flame went still. The mana pressure shifted, heavy and hard and sharp. Tiamat's wings flared half-open.
"Choose," she said quietly, "your next words very, very carefully, dragon-cub."
"I came," I continued, unwavering, "to offer to find it."
Her eyes — those cold, ancient things — widened just a fraction. If I hadn't already been watching her like my continued existence depended on it, I'd have missed it.
"You?" she asked slowly. "A half-baked, half-dragon hatchling? You would search for something even full grown dragons have failed to track?"
"I would," I said. "But I want something in return."
Silence fell so hard it rattled my teeth. Then she chuckled — low, rich, dangerous. It rolled around the cavern like thunder flirting with landslides.
"You negotiate like a devil," she said, almost amused. "What do you want, then? Wealth? Power? One of my scales? A fragment of my fang? Something foolish and greedy, the way your kind always does?"
I shook my head. "I want training."
She stared.
"Training," she repeated, just to make sure I heard how stupid that sounded.
"Not just for me," I said. "For two others: Kalawarna and Asia."
Her brow rose. Her tail stilled mid-swing. "You want me—the Chaos Karma Dragon, Queen of the Middle East, scourge of the Blue Flames, nightmare of pantheons—to train you and your little entourage?"
"Yes."
"Why?" No jest this time. No mockery. Just a sharp, straight question. "For what purpose?"
"To protect my family," I said simply. "To protect those who rely on me. To avoid wasting the power I've been given… and the dragon who's stuck with me."
It wasn't poetry, but it was honest. Something flickered in her eyes. Respect. Irritation. Curiosity. All three, swirling. She lifted one hand. Blue fire coiled around her fingers like affectionate serpents.
"Very well, little Spark," she said softly. "I will entertain this outrageous request. I will make a contract with you."
Blue aura swirled around us like storm clouds gathering. The cavern hummed with sudden structure — draconic magic setting rules, snapping them into place like vertebrae.
"But hear my terms," she continued, voice dropping lower. "And understand them. I hate repeating myself."
I nodded once. "Go on."
"You will find my treasure," she said. "Wherever it sleeps, whoever holds it, whatever it has become."
"Fair."
"You will not lie to me." Her eyes gleamed. "A dragoness hates liars. And I, little Spark, am terrible at forgiveness."
"Noted," I said. "No lying."
"You will accept my training without complaint," she said. "No matter how painful, humiliating, or… enlightening."
"Define 'complaint,'" I said.
"Any noise I don't find entertaining."
"Got it."
"And if you break the contract," she finished, lips curling into a smile that was all teeth and doom, "I feed you to my hoard. Slowly."
"…Reasonable," I said.
Her eyes narrowed, amused. "You say that without hesitation. Are you foolish… or fearless?"
I held out my hand. "Your terms… and mine."
She looked down at my hand like it was something unusual. Not disgusting. Not pathetic. Just… rare. After a moment, she extended her own and placed her palm against mine. Her skin wasn't soft. It felt like warm stone, tempered steel, and live flame, all at once. The contract responded instantly. Blue fire roared to life around our joined hands, spiraling upward. Crimson light answered from my side, Ddraig's power awakening in tandem. Ancient runes bled out of the air, sliding into existence like living scripture written by volcanoes and storms.
[She's binding the pact.] Ddraig said, tone serious. [Dragon-style. No loopholes. No backsies.]
'Good.'
The flames coiled around us both, then sank into skin. I felt something sear across my chest — not pain, but weight. A new mark etched into the soul. Tiamat's aura flared, then settled, threads of her power brushing against mine. When the glow faded, she exhaled slowly and withdrew her hand, flexing her fingers once. Her wings settled around her shoulders like a cloak.
"It is done," she said.
I pulled my hand back, flexed it. It still worked. That was a good sign.
"Then I'll find your treasure," I said.
"And I," she answered, with draconic pride and a hint of challenge, "will make you into something worthy of carrying his soul."
Her eyes narrowed, more focused now. "Bring the Fallen woman and your little saint tomorrow. Training begins at dawn."
"Of course it does," I muttered.
She smiled like she'd heard that. Which, considering this was Tiamat, she probably had. I turned toward the tunnel I'd entered through, legs aching but steady.
[Partner…] Ddraig said slowly. [I think we might be in trouble.]
'Good, I thought. Trouble's how I grow.'
[I said trouble, not therapy.]
'Same thing, apparently.'
Behind me, Tiamat's voice followed, soft and lethal.
"Do not disappoint me, Red Dragon Emperor."
The cavern's light brightened briefly — a surge of mana, the contract sealing deeper. Then it dimmed again, returning to its steady sapphire heartbeat. I stepped out of the Dragon's Den and back into the forest, the weight of a new future sitting on my shoulders like a dragon's shadow. The Familiar Forest greeted me with its same impossible green and star-lit canopy. But now the air felt different — like the place had watched the deal and decided not to eat me. For now. I walked until I hit the border where the mana density dropped enough that a normal devil wouldn't choke on it. A crimson sigil flared to life under my feet — the return circle Rias had keyed to my aura.
One breath. Home. The world twisted, and the Underworld folded away. I stepped into the Hyoudou living room like I'd never left. The TV was on some comedy show. My father laughed too loud at a joke that barely qualified as humor. My mother shook her head, smiling. Kalawarna sat on one of the armchairs, legs crossed, her posture deceptively casual. Asia sat on the sofa, hands wrapped around a mug of tea, eyes fixed anxiously on the magic circle that had just spat me back into domesticity. The circle vanished. I took one step forward, from the quiet spot, and made myself present. Asia launched out of her seat.
"Issei-san!" she cried, nearly dropping her mug, then remembered herself and set it down before running to me. "You're back!"
"Hey," I said, raising a hand. "Told you I would be."
Her gaze swept over me, eyes widening. "You're… burned."
Right. I'd forgotten about that. Parts of my shirt were scorched. My arms still bore faint red lines where Tiamat's breath had kissed me.
Kalawarna stood, eyebrows climbing. "You look like you argued with a volcano and lost on points."
"Won," I corrected. "Barely. We drew."
She studied my face for a moment. "You met her."
"Yeah. She has… opinions."
Kalawarna's lips tightened. "And?"
"And we have a contract."
She stared. Asia gasped softly.
"With Tiamat?" Kalawarna asked, just to confirm I'd chosen maximum insanity. "The Chaos Karma Dragon? The one Azazel wanted to approach and then decided he liked not dying more?"
"The very same," I said.
"Of course," she muttered. "Why not. Let's invite the apocalypse to brunch."
Asia tugged at my sleeve, eyes worried. "Issei-san… are you really okay? You look… hurt."
"I'll be fine," I said. "It's just my aura throwing a tantrum. My body will catch up."
"Sit," Kalawarna ordered, pointing to the chair in the dining room.
"Bossy," I said, but I sat.
Asia hovered at my side, hands glowing faintly with her healing power, waiting for a signal. I nodded. Warmth flowed through my burns — soft, bright, not like Tiamat's fire at all. The pain receded, nerves relaxing one by one.
Kalawarna folded her arms and leaned against the wall. "So," she said. "Let's hear it. What are the terms?"
"Tiamat trains us," I said. "Me, you, Asia. Dawn. Tomorrow. In her den."
Kalawarna stared. "In… her den."
"Got a problem with caves?"
"Only when they contain legendary dragonesses with personality disorders," she said flatly. "Azazel is going to lose his mind from sheer academic jealousy."
Asia blinked. "She… agreed to train me too?"
"She knows about you," I said. "Called you my 'little saint.' Didn't snarl when she said it. That's about as close to affection as she gets."
Asia's cheeks flushed, eyes wide. "A dragon will… train me?"
"Yeah. You scared?"
"A little," she admitted. "But also… happy."
Kalawarna groaned. "She's going to weaponize your kindness," she muttered. "We're doomed."
[I am not sure if I am more worried or impressed,] Ddraig said in my skull. [You convinced Tiamat to enter a contract. That alone should be impossible. Almost as impossible as the fact that she didn't just tear your heart out on principle.]
'She owes you a beating, not me.'
[She owes me several.] Pause. [She will use you to hit me.]
'Yeah. I counted on that.'
[You are a terrible partner.]
'You love me.'
[Regrettably.]
Dinner was normal. Too normal. Curry, stupid jokes, the comfortable weight of domestic noise filling the house. Asia helped Mom clean up; Kalawarna pretended not to care about dessert and then stole an extra portion. I stayed quiet, letting my body rebuild itself while my mind walked circles around what tomorrow would be.
Training under Tiamat.
Not sparring. Not coaching. Training.
The kind that breaks you into small, screaming parts and puts you back together wrong in exactly the way you need to survive what's coming.
When the house settled — TV off, hall lights dimmed — the three of us gathered in the warehouse.
Our base. Our little den.
Asia sat on a crate, legs tucked together, hands clenched in her lap. Kalawarna leaned against a pillar, arms folded, eyes narrowed in thought.
"So," Kala said. "Tell us everything. Don't leave out the part where she tried to cook you."
"She tried to cook me," I said. "Trial by flame. Survive her breath or fail the 'entrance exam'."
Asia's eyes went saucer-wide. "That's horrible…"
"That's draconic," I corrected. "She wasn't trying to kill me. Just erase me if I wasn't worth the explanation."
"That's worse," Kalawarna muttered.
I described the cavern. The mana pool. The old glyphs. The trial. The contract. How Tiamat talked about dragons like they were gods cursed to walk in chains. How she'd looked at me like she'd already seen ten possible futures and was deciding if any of them interested her.
"And the treasure you spoke of?" Kalawarna asked.
"Something Ddraig 'borrowed' and 'forgot' to give back."
Kalawarna pinched the bridge of her nose. "Of course. I work for an over-caffeinated Governor General and my teammate is in debt to a dragon queen. My life choices are flawless."
Asia looked between us, confused. "Is it… very important, this treasure?"
"Tiamat still cares," I said. "That makes it very important."
"Treasure," Kalawarna said, "for dragons, isn't about shiny things. It's about proof they existed. Their legacy, condensed. Artifacts. Weapons. Promises. Philosophies made metal. You don't 'borrow' that. You make a blood pact and die trying to keep your end."
Asia swallowed. "And Ddraig-sama…?"
[I INTENDED to return it,] Ddraig said, grumbling. [Then a lot of people tried to kill me. And then I got sealed in this thing. Time management was… complicated.]
"Excuses," I said aloud.
[Correct.]
"We'll find it," I said. "Somehow. Somewhere between missions and not dying."
Kalawarna raised a brow. "You sound confident."
"I have to," I said. "Contract's binding. Screwing this one up isn't an option."
"And if she kills you during training?" Kalawarna asked.
"She won't," I said.
"How can you be sure?"
"Because dragons don't burn books they haven't finished reading."
Kalawarna stared for a moment, then snorted. "That's either the smartest or dumbest thing I've heard you say."
Asia tugged at her sleeve. "Um… Kala-san… are you scared?"
Kalawarna thought about it. Really thought. Then smiled crookedly. "Anyone with a brain is scared. But I'm also excited. It's Tiamat. If she trains us, we stop playing on the kiddie difficulty."
"Hard mode unlocked," I muttered.
"Legendary suicidal mode unlocked," she corrected.
Asia nodded, eyes serious. "Then… I'll do my best. I don't want to be a burden."
"You're not," I said, more sharply than I intended.
Both of them looked at me.
"Asia," I said more softly. "You are not a burden. You're our healer. Moral compass. Official 'don't turn into psycho murder machines' buffer. That's critical."
She smiled, small but bright. "Then I will be the best buffer I can."
Kalawarna laughed. "We're doomed, but adorably."
Sleep came in pieces. Short, sharp pockets between thinking and worrying and imagining Tiamat's voice saying "Pathetic" in different tones. Morning — human morning — arrived. The Underworld didn't care. Tiamat had said "at dawn," and dragons did not mean "8:30 after you stretch." The teleport sigil provided by Rias pulsed to life in the warehouse at exactly 5 a.m. Asia stood in a fresh set of practical clothes — simple shirt, flexible pants, sturdy shoes — hair tied back. She still radiated "innocent nun" energy, but at least she looked less likely to trip on a hem and die. Kalawarna wore a sleeveless cropped top, tight around her big jugs marking her nipples, tight training pants that molded itself to her ample buttocks and her camel-toe-shaped pussy, and light armor plates over vital areas, long hair pulled into a high ponytail. Fallen Angel elegance turned tactical. I wore my usual training gear: reinforced sleeveless red shirt, loose cargo pants, good boots, wraps on forearms. Boosted Gear simmered under the skin.
"You ready?" I asked.
"No," Kalawarna said. "Let's go."
"Yes," Asia said, then whispered, "I'm a little scared," like it was a secret.
"Good," I said. "Stay that way. Fear keeps you alive. Panic gets you killed. Learn the difference."
The sigil expanded. Light swallowed us. We arrived back in the Familiar Forest — deeper, this time. Rias must've adjusted the coordinates. Or Tiamat had dragged the exit. The mana density hit like a truck. Asia gasped. Kalawarna winced.
"Breathe shallow," I said. "Don't fight it head-on. Let it slide around you."
They adjusted. The pressure eased slightly. A trail of glowing blue wisps — not quite will-o'-the-wisps, not quite spirit particles — bobbed in the air ahead of us, forming a path.
"Tiamat's version of a welcome mat," I said. "Follow it. Don't wander off. The forest… judges."
Asia nodded vigorously. Kalawarna muttered something rude about magical ecosystems. The path took us faster this time. The forest remembered me now, and didn't bother with preliminaries. Trees leaned back. Roots withdrew. The pulse underfoot grew stronger. The cavern mouth loomed again.
Kalawarna stopped dead. "…Oh."
Asia grabbed my sleeve and didn't let go.
"Remember," I said quietly, "no bowing unless she makes a point of it. Don't pull any holy stuff out without warning. Don't lie. Don't flirt—"
Kalawarna opened her mouth with a grin.
"—with her," I finished.
"Ruin my fun, why don't you," she said.
We stepped into the cavern. Tiamat waited in humanoid form, perched casually on a stone outcropping like the most dangerous gargoyle in existence. Her wings were half-furled today; her hair flowed loose; she wore a different outfit — still functional, still regal, this time a long-slit coat over fitted underclothes, all shades of blue and white. She looked like a mix between a battlefield commander and a goddess having a bad day. Her gaze swept over us as we entered. It lingered on Asia. Then on Kalawarna. Then on me.
"I see you brought them," she said. "Good. I was beginning to worry you fainted on your way back."
"Not my style," I said.
"Mm. We'll see."
Asia did a polite bow. "I-It's an honor to meet you, Tiamat-sama."
Tiamat's eyes narrowed slightly. "You smell like church," she said. "But your light doesn't bite. Acceptable."
Asia froze, then smiled nervously. "Th-thank you… I think…"
Tiamat shifted her gaze to Kalawarna. "Fallen," she said. "Grigori. Tainted by Heaven, rejected by Heaven, now dancing in the dark."
Kalawarna smirked, bowing her head a fraction. "You do get around, don't you? Big fan of your work, by the way. 'Queen of Dragons' is a hell of a brand."
Tiamat's lips twitched. "Flattery from a crow. Mildly entertaining."
Her focus returned to me. "And you, little Spark. You brought your flock. Good. It will be useful to have witnesses when you despair."
"Motivational," I said dryly.
She stood, motion fluid and eerily quiet, and stepped off the rock. The cavern trembled just a little, like it was obeying, not reacting.
"This training," she said, "is not a gift. It is not charity. It is not indulgence."
Blue fire coiled around her like a halo. The pressure in the cavern spiked.
"It is an investment," she continued. "I will not waste my time on weak creatures who cling to excuses. You will break. Repeatedly. Your bodies. Your minds. Your assumptions. I will unmake the parts of you that displease me and rebuild only what has potential."
Asia swallowed audibly. Kalawarna's jaw tightened, but she didn't step back.
"And when I am done," Tiamat said, "you will be either dead… or worthy."
Her gaze cut to me. "Do you still accept, Hyoudou Issei?"
"Yes."
She turned to Kalawarna. "Do you accept?"
Kalawarna's eyes flashed. "I don't back down when the stakes are this high."
Tiamat's focus slid to Asia. "Little saint."
Asia trembled, then nodded. "I want… to stay by Issei-san's side and help. So… please train me. Even if I cry."
Tiamat's expression changed — for just a fraction of a heartbeat. Something like approval flickered there.
"Good," she said. "Lesson one, then."
She snapped her fingers. The ground dropped. The cavern floor vanished. For a dizzying instant, all three of us plummeted in a shaft of sapphire light. Asia screamed — brief, startled, then cut herself off, forcing her own breathing steady. Kalawarna cursed. I just squinted as wind roared around us. Then the fall stopped.
No impact. One moment down, the next — still.
We stood on solid ground in another chamber, deeper, wider, and somehow more alive than the last. It was a training field carved by dragon whims — pillars of obsidian, floating platforms of impossibly suspended rock, pools of mana, sigil circles carved directly into the floor.
"Welcome," Tiamat's voice echoed from everywhere, "to my Den of Trials."
A flash of blue — she appeared at the far edge of the chamber, arms folded, wings spread wide.
"Here," she said, "we begin."
[Oh, this is going to hurt,] Ddraig muttered.
'Good,' I thought. 'I haven't hurt enough yet.'
Tiamat smiled — slow, sharp, delighted.
"As expected," she said, eyes gleaming. "Your flame hasn't gone out yet."