Heroine-Saving System: Reborn In A Third-Rate Manga As The Protagonist-Chapter 83: Saeko’s Vault

"Why did you..." Nami stuttered as she swerved the steering wheel sharply, almost hitting another car merging onto the main road. "Spit it all on me...?"

"Sorry." Koya said while materializing a clean napkin from his storage ring and carefully cleaning where the water had splashed... it was on her face, her hair, her hands, and even a bit on her collar. "I just thought of something really weird."

Reona finally finished her ice cream cup and extended both hands toward him with an expectant expression.

"Onii-chan... another one." She said while patting her tummy with a thoroughly satisfied smile. "You bought a lot of ice cream after all."

"I was planning to give some to Yuu and Akemi as well as Yuna when we get home," he said. Apparently the three girls at the mansion loved ice cream... he had even called ahead to confirm their favorite flavors before purchasing. "I bought an additional cup for myself too."

"Onii-channn~" Reona’s voice took on a wheedling tone. "You still have like one extra cup though..."

She pointed out the obvious with big puppy-dog eyes. Koya sighed in defeat before materializing the last cup in his hand. It was still perfectly cold thanks to his storage preservation and he handed it over to her.

"I love you, Onii-chan~" she sang happily.

"Of course you do..." Koya grumbled under his breath.

Nami chuckled at the sibling dynamics before focusing back on the road ahead.

She wanted to make some sort of perverted remark about him spitting water all over her face, but decided against it since Reona was in the car.

’Later.’ she promised herself.

Now that the car was silent again, apart from the soft music playing through the speakers, Koya focused on the System notification screen floating in his vision.

He saw what had made him spit out his water so violently.

「You have received Black Dragon Egg from the Super Mystery Box」

Once again, he didn’t know how to react to this discovery. It seemed today was absolutely full of insane activity.

Dragons somewhat existed in this world as incredibly powerful monsters, of course. Legendary creatures that could level entire cities.

Most were classified as Gold-class threats or higher and they were the kind of beasts that required entire military divisions or Silver Crest Awakened to handle.

’System, please run a comprehensive scan comparing this egg with any other Black Dragons that might exist in this world...’

「Scanning global monster database...」

"Koya... do you like this kind of music?" Nami asked as she smoothly swerved the car into another lane.

Koya actually listened to what was playing through the speakers for the first time. It sounded quite like an anime opening theme song with soaring vocals.

"It’s the opening theme to one of these new anime adaptations," Nami explained. "It’s called Fate X and it’s pretty popular right now."

"Oh, I read the manga of that a while ago actually. It has an anime adaptation now? It’s been a while since I checked." Koya muttered, making mental notes.

Now he’d have to schedule some new streaming content, which meant studying more manga series and keeping up with seasonal anime. ’My life is so damn stressful.’

"Oh, Koya-kun... you read manga too?" Nami perked up with genuine interest.

"Onii-chan doesn’t only read manga but he str—"

Koya gave her an absolutely withering glare. She shut up immediately, clamping her mouth closed. They were NOT supposed to talk about his streaming career out in the open. That was classified information.

"Str?" Nami asked while glancing between both of them in the rearview mirror. "Come on... why aren’t both of you talking? What were you about to say?"

"It’s nothing that serious," Koya deflected smoothly. "I was just a bit of a manga nerd before I awakened. Read constantly to pass time."

The theme song kept playing as he refocused on the System notification tab floating in front of his face.

「Scan Complete」

「Species: Black Dragon (Legendary)」

「Physical Characteristics: Obsidian-black scales with natural mana absorption properties. Adult wingspan approximately 30 meters. Capable of flight at speeds exceeding 400 km/h.」

「Breath weapon: Void Flame... black fire that consumes both matter and mana.」

「Current Population: Only ONE adult Black Dragon exists in this world... a Gold-class monster residing deep within the uncharted territories outside the Outer Zones and considered a multi-city-level threat, has not been sighted in over 50 years.」

「Reproduction Rate: Extremely rare. Black Dragons lay eggs once every century.」

’Nice...’ Koya thought, genuinely pleased. If trained properly and bonded from birth, it would become an incredibly powerful familiar.

After all, monster taming and familiars definitely existed in this world. Monsters could be captured and trained instead of killed outright but the stress of taming something found in the wild was astronomically high... the beast would always retain its wild instincts and could turn on you.

It was infinitely better if you bonded with them from the moment they were born. It would foster absolute loyalty

He pulled up his second Regular Mystery Box mentally while Nami drove.

「Would you like to open Regular Mystery Box?」

「Y / N」

He selected Y. The animation played... this time it was a simple wooden box opening with basic particle effects.

An item materialized in his System inventory.

「You have received Succubus Panties (Rare) from Regular Mystery Box」

「Item Description: Enchanted undergarment that dramatically increases the wearer’s sexual appeal and pheromone output.」

Koya’s eye twitched violently.

’System, what the hell is wrong with your loot tables?!’

「Host received items appropriate to current life situation and relationship developments ( ͡° ͜ʖ ͡°)」

’Don’t you dare use that emoticon at me, you piece of—’

The car pulled smoothly into Star Mansion’s driveway... The servants opened the gates and soon she parked in the spacious garage, getting out with a long stretch that made her back pop satisfyingly.

Reona did the same, already finished with her second ice cream cup.

Koya exited the passenger side and immediately noticed Bobby approaching from the mansion entrance.

The other two girls walked inside, leaving him alone with the silent enforcer.

"Yo." Koya greeted casually. This was the guy Hakai had sent to brief him on yesterday’s assassination mission.

Was he here to discuss another contract? "What’s up?"

Bobby simply brought out a folded piece of paper and shoved it forward wordlessly. Koya took it and the man immediately walked off without a sound.

"Right... he doesn’t speak." Koya muttered under his breath.

He really had the intrusive thought to jab his finger directly into the man’s eye socket just to see if he’d finally make a noise. Would he scream? Or just bleed silently?

Koya unfolded the paper and read the neat handwritten text.

[Saeko’s personal vault has been completely looted by Disguise Master as ordered. The contents... which are your mission reward have been securely placed in a secret floor of the mansion. Follow me to reach the location. The access codes have already been programmed with your biometric data.]

Koya crumpled the paper and looked toward where Bobby had already disappeared into the mansion.

"You should have just said so instead of writing it..."

...

It turned out that the entire underground level of Star Mansion was far more extensive than Koya had initially realized.

He’d thought it was just Hakai’s private office and maybe some storage rooms. However, as Bobby led him down multiple flights of stairs... going deeper and deeper underground, he activated his Sensory skill and was shocked by what he detected.

There were dozens upon dozens of secret rooms... twisting pathways, hidden chambers, interconnected tunnels, storage vaults, training facilities and so much more.

Even with his current mastery level of Sensory, he couldn’t map all of them completely. The underground network was absolutely massive.

They finally reached a specific reinforced door after descending what felt like five floors underground.

Bobby nodded once, then handed Koya another note before walking off into the shadows.

Koya read it:

[Place your hand on the biometric scanner located below the door handle. Your biometric data was registered today from the spanks you gave Boss during your... activities. This room is now YOUR personal vault. Nobody else will be able to access it... not even Boss herself. Complete privacy guaranteed.]

Koya didn’t feel even slightly embarrassed as he pressed his hand flat against the biometric scanner pad.

It beeped with confirmation.

[ACCESS GRANTED: AMAGI KOYA]

The heavy reinforced door unlocked with multiple mechanical thunks and slid open smoothly. What lay on the other side made his jaw drop.

The room was absolutely enormous... it was roughly the size of a small warehouse with industrial shelving units lined every wall from floor to ceiling, each shelf meticulously organized and labeled.

There were glass containers, sealed jars, climate-controlled storage boxes filled with rare medicinal herbs and mana-infused materials.

In the very center of the room sat a massive worktable made of polished black stone... easily three meters long and two meters wide.

"Damn... nice room." Koya walked inside slowly, taking it all in as the door locked behind him.

The place smelled intensely of medicinal herbs. It was overwhelming but not unpleasant. The scent of pure wealth.

He was about to materialize the dragon egg from his inventory to examine it properly, but paused.

’System, check this entire room for hidden cameras and monitoring devices.’

「Checking for surveillance equipment... please wait...」

「Scan complete. There are NO hidden cameras, audio recording devices, or mana-detection sensors in this room. It is completely clean and secure.」

He did another manual sweep with his Sensory skill just to be absolutely certain, checking every corner, every shelf, even inside the ventilation system.

「Host doesn’t trust me... waahh (╥﹏╥)」

’You can’t even actually speak or cry. Emoting through text is weird, dumbfuck.’ Koya thought as he finally accepted the Super Mystery Box reward properly.

The Black Dragon Egg materialized in his arms.

It was heavy... easily twenty kilograms or so and large too, it was roughly the size of a basketball, maybe slightly bigger but it weighed so much.

The shell was pure obsidian black with crimson veins running through it like lava flows. It was warm to the touch.

A small sealed container had appeared with it, attached to the bottom. Koya carefully set both items on the massive workbench.

"It’s a really heavy egg... and there’s instructions with it too."

He opened the container and pulled out a detailed instruction scroll with neat handwriting.

[BLACK DRAGON EGG: CARE INSTRUCTIONS]

[Daily Mana Feeding: Must channel pure mana into the egg for exactly 10 minutes every single day. Missing more than 2 consecutive days will result in the embryo dying permanently.]

[Environmental Requirements: Egg must be surrounded by high-concentration elemental mana sources. Recommended: Fire-element materials (primary), with secondary elements as supplements. The richer the mana environment, the stronger the hatched dragon will be.]

[Hatching Timeline: Estimated 30-45 days with proper care.]

[Bonding: The dragon will permanently imprint on the first person it sees upon hatching. This bond is unbreakable.]

[Warning: Adult Black Dragons are continental-level threats. Ensure proper training from birth.]

"It’s going to be quite difficult to take care of this egg properly..." Koya set the instruction scroll down on the table. "Good thing this is Saeko’s personal vault..."

He looked around at the absolutely massive collection of materials.

"System, run a comprehensive analysis. First: identify all available elemental-affinity items suitable for dragon egg incubation. Second: catalog every supplement and ingredient here and check if we can use them to make pills."

「Searching elemental items... Please check the top shelf of Unit #4 for Fire-element materials」

Koya walked over to the numbered shelving system, found Unit #4 and looked up at the top shelf. There were dozens of small crimson orbs roughly the size of baseballs, glowing with inner heat.

「Item Name: Fire Stone」

「Description: Concentrated Fire-element mana crystallized into physical form, it can be absorbed during rank advancement from Four-liner to Blue-liner to bolster fire elemental mana」

’Oh?’ Koya examined the orbs more closely. ’I’ll definitely need these when I advance to being a blue-liner.’

He glanced back at the dragon egg sitting on the workbench, then grabbed three Fire Stones and carefully arranged them around the egg in a triangle formation.

Then he grabbed the rest... roughly fifteen more stones and stored them in his System inventory for personal use later.

He continued searching through the shelves systematically. He located Lightning Stones (brilliant blue), Earth Stones (deep brown) and even wind Stones (pale green).

’Since my current affinities are Blood, Lightning, and Fire... wait, four including Darkness from Hakai,’ Koya thought while organizing. ’I’ll keep the ones aligned with my elements for personal cultivation, then use Earth and Wind stones to feed the dragon egg.’

He arranged twelve stones total around the egg now... three of each type and the egg seemed to shake slightly, as if sensing the mana-rich environment.

’Now I need to actually feed it mana for the first time...’

Koya activated Mana Mode, feeling the ambient energy flood into his body then he placed both palms directly on the egg’s warm surface and began channeling. Pure mana flowed from his reserves into the egg in a steady stream.

The black shell glowed with crimson light and it trembled slightly against the table. All twelve stones surrounding it began glowing simultaneously, their power being greedily absorbed.

As he fed the egg, Koya whistled casually and checked the System’s analysis results.

「After examining every available substance in this vault, Host possesses sufficient materials to create 150 distinct variations of pills and potions」

’Filter the list. Show only items useful to me specifically.’

「Useful formulas reduced from 150 to 98」

’System, how many finished supplements are actually stored here already?’

「There are approximately 486 finished supplements including healing pills, mana recovery potions, and attribute enhancement drugs」

"Show them to me," Koya said aloud.

After finishing the required ten minutes of mana feeding, he walked to the far edge of the vault. There was a massive reinforced safe built into the wall with another biometric scanner mounted beside it.

He pressed his hand against it.

BEEP!

The heavy door unlocked and swung open. Inside were countless bottles and vials of glowing liquids, also there were sealed containers with powders.

Everything was meticulously categorized.

Koya took a deep sniff. It smelled exactly like high-grade drugs and he couldn’t help but laugh.

"Hehehehe... I honestly wouldn’t mind being a full-time assassin for the Order if I got rewards like this every mission."

「Ding! You are receiving a FaceTime call from HeroGod. Would you like to answer?」

He pulled back and straightened his collar.

Koya had been talking to HeroGod quite frequently, and they’d become close friends. There was a trading function that allowed item transfers.

He was on the verge of convincing her to send him some items from her apparently limitless treasury.

"Answer the call."

...

A black limousine slowly made its way through the streets toward Star Mansion. Inside, Victoria and Hakai sat opposite each other.

Though there were no scratches on their faces, their clothes were absolutely shredded. One of Hakai’s breasts was completely exposed through torn fabric while Victoria’s thighs were fully visible through massive tears.

They’d gone all-out during sparring.

Hakai turned to Disguise Master, who sat with both hands pressed against her face. It was the Head maid from the store.

"I know we accidentally killed your clone during the fight... I’m genuinely sorry." Hakai looked apologetic.

"Me too," Victoria added. Disguise Master also had the ability to create a single perfect clone... though it was just one at a time.

After being initially blasted off the mountaintop, the clone had tried to climb back up. However, wind pressure from one of Hakai’s punches had literally severed the clone’s hands... It had fallen hundreds of meters and splattered.

"At least your main body was still working at La Belle Étoile," Hakai said. "How was today’s shift?"

"I’m not offended about the clone," Disguise Master spoke.

First she’d seen Nami’s breasts in that bikini, now these two were practically naked. She felt like she might pass out. "Work was fine. Your husband came by and purchased quite extensively."

"I see... He should learn to spend money extravagantly on himself more often." Hakai said with a fond smile.

Disguise Master was internally speechless. How was she supposed to say Koya had spent 1.5 million crowns on gifts for everyone EXCEPT himself?

’Whatever... I should just enjoy this view,’ she thought as she looked at both women properly.

SPLURT.

Blood shot from her nose again.

"Are you... feeling okay?" Victoria raised an eyebrow.

The limousine soon pulled into Star Mansion’s garage and the three women exited. The mansion seemed lively inside though.

Hakai walked off separately, and once out of sight, she melded into shadows and teleported to her underground office.

She had more contracts to review and needed to decide which mission she’d send Koya on next.

Victoria walked inside and immediately found Yuu... still in her school uniform running and playing tag with Reona.

"Reona, where’s Koya...?" Victoria asked.

Reona dodged Yuu and placed a hand on her chin. "I think Onii-chan went to your roo—"

She hadn’t finished.

Victoria ran at full vampire speed which made her a complete blur. Reona shrugged and hugged her new scarf. Onii-chan had been distributing gifts like Santa Claus.

Currently Akemi and Yuna were in their rooms savoring their presents.

Victoria burst through her bedroom door.

She saw Koya adding finishing touches to a massive teddy bear on her bed which was easily four feet tall, wearing a tiny tuxedo.

The moment she saw him, she ran and jumped into his arms.

He caught her easily. "Whoa, you seem really excited."

She nodded against his chest, breathing in his scent. "I’m so happy to see you, hubby."

She hugged tighter. "You’ll sleep in my room tonight..."

"Oh, but what about Hakai?"

"We sparred to determine whose room, and we fought to a draw," Victoria explained while looking at his crimson eyes. "So we played rock-paper-scissors, and I won fair and square."

She pouted adorably. "So you’re sleeping in my room and doing everything you did with Hakai to me too... right?"

He patted her head. "Sure then. We’ll do everything as long as you genuinely want it."

Her eyes literally lit up.

"Really? You promise?"

Hakai said it was a secret and she wanted to know what that secret was... What had they done that had left her so bruised but happy?

He nodded then she noticed the giant teddy bear. "Hubby, is that a gift for me?"

"Yes... I bought several gifts for everyone." He motioned to packages around the room. "Now, I don’t think you lack anything material, but—"

She interrupted by pulling his face down and kissing him directly on the lips. It was just a simple lip kiss with no tongue but it was heartfelt.

She drew back with her face flushed. "Thank you so much, hubby..."

Koya suddenly had the enchanted panties in his hand and pulled from inventory.

"Huh...? What’s this?" Victoria tilted her head.

"It’s a very specific pair of panties I bought at the boutique," he lied smoothly. "I’d really like you to wear them tonight..."

She nodded without hesitation and immediately began removing her shredded training pants, revealing underwear completely soaked with sweat.

She casually threw the sweaty panties toward the laundry basket, along with her torn clothes and she was standing in just her sports bra now.

Just then, Disguise Master... dressed as Head Maid knocked and entered to collect laundry.

"I’ll be taking your laundry, my lady," she said formally while lifting the basket but her eyes were glued to the discarded panties.

A barely concealed lewd smile spread across her face as she walked out and Victoria stepped into the Succubus Panties and pulled them up.

They were indeed extremely tight... hugging every curve of her ass.

She looked down, adjusting slightly. "The panties are a bit tight, hubby, but they fit okay."

Then she noticed Koya staring down intensely... like he was trying to see through the fabric with pure willpower.

"Hubby?" She waved her hand. He snapped out of his trance with a nervous laugh.

’When did I become this obsessed with sex...?’

"Let’s go spend some time with the other girls downstairs," he suggested quickly.

She nodded and pulled on comfortable casual clothes and they walked out together, hand in hand.