Asagi stared at him like he'd just confessed to blowing up the moon.
"What do you mean you got an upgrade?!"
Leo winced. "Okay, first of all, inside voice."
Asagi pointed at his arm. "No. Outside voice. Very much outside voice."
With a nervous sigh, Leo let the Blacklight crawl over his forearm.
The tendril burst out, thicker than before. Darker. Jagged ridges ran along it like armor plates, and sharp spikes pulsed faintly red at the edges.
Asagi took a step back. "Y–you already had tendrils!"
"I know," Leo said quickly. "But these are… different."
He flexed his fingers.
The tendril split into three smaller whips, each lined with hooked barbs.
"They're more solid. More… aggressive. And they can harden into blades or shields now."
He pulled the Blacklight back into his skin. His arm went normal again.
"And no," he added, rubbing the back of his neck, "I was not expecting this either."
Asagi dragged both hands down her face.
"So let me get this straight. You went to investigate a spooky glowing classroom—"
"Yes."
"—found a girl doing demon magic—"
"She's a mage."
"—got blasted by a spell—"
"Technically, yes."
"—and now you have murder tentacles with DLC features."
Leo opened his mouth. Closed it.
"…When you say it like that, it sounds bad."
Asagi slowly turned her head toward Yuuko.
Yuuko shrank in on herself, clutching her spellbook to her chest.
"And you," Asagi said calmly, which was somehow scarier, "are responsible for this."
Yuuko bowed so hard her forehead nearly hit the floor.
"I–I'm so sorry! I didn't mean to! The summoning circle destabilized and the energy rebound and then his aura absorbed it and I thought he was going to turn into an eldritch horror and I panicked and—"
She sucked in a breath.
"I'll take responsibility! I'll do whatever you want!"
Asagi blinked.
Leo coughed. "Please don't say it like that."
Yuuko looked up, cheeks bright red. "I–I meant magical responsibility!"
"…That also didn't help," Leo muttered.
Asagi pinched the bridge of her nose.
"So. You're a witch."
Yuuko nodded. "Yes."
"You accidentally powered up my fiancé."
"Yes…"
"You think he's a Fuuma demon."
"…Also yes."
Leo raised a finger. "In her defense, that one's on the clan's branding."
Asagi shot him a look.
He immediately lowered the finger.
Asagi turned back to Yuuko.
"…Are you dangerous?"
Yuuko hesitated. "To other people? Not really. To myself? Constantly."
Leo nodded. "Accurate."
Asagi sighed deeply and slumped onto the couch.
"This is my life now. I grew up fighting demons and now my future husband is one."
Leo sat beside her. "Half demon. Technically. Maybe. Spiritually."
She leaned her head against his shoulder.
"…You're not leaving me, right?"
Leo didn't even hesitate.
"No. Never."
That was when Yuuko's grip on her book tightened.
"…You saved me," she said quietly.
Both of them looked at her.
"You didn't have to. You could've run. You could've let the entity take over the classroom. You could've let it take me."
Her voice trembled.
"But you didn't."
Leo scratched his cheek. "Yeah well. That thing was ugly and you looked like you were about to pass out."
Yuuko stepped closer.
"And then you absorbed it. Like it was nothing."
Her eyes shone.
"I've spent my whole life being scared of the things I summon."
She bowed again.
"…Please let me stay with you. I don't feel safe anywhere else."
Asagi stiffened.
Leo opened his mouth—
Yuuko dropped to her knees.
"And I think I'm in love with you."
Dead silence.
Leo's soul left his body for three seconds.
Asagi slowly stood up.
Leo panicked. "Okay, listen, this was not part of the plan, I swear—"
Asagi walked past him.
Stopped in front of Yuuko.
Looked down at her.
"…You really picked the worst possible man."
Yuuko nodded. "I know."
Asagi exhaled.
Then held out her hand.
"If you're staying, you follow the rules."
Yuuko stared at it like it was holy.
"R–rules?"
Asagi smiled.
The scary one.
"Rule one: You don't try to steal him."
Yuuko grabbed her hand immediately. "I swear on every grim reaper I know!"
Leo blinked. "You know grim reapers?"
Asagi ignored him.
"Rule two: You don't summon anything in my house without permission."
Yuuko nodded furiously.
"Rule three…"
She glanced at Leo.
"…You help keep him human."
Yuuko swallowed.
"…I will."
Asagi released her hand.
Then turned to Leo.
"…You owe me ramen for life."
Leo sighed in relief.
"Deal."
Asagi stepped closer.
"One more thing," she said calmly. "Since we keep getting interrupted."
She grabbed Leo by the collar and pulled him down.
Leo blinked once.
Then closed his eyes.
They kissed.
It wasn't their first kiss.
But it still made his chest tighten the same way it always did.
Warm. Familiar. Safe.
After a few seconds, they pulled apart.
Asagi rested her forehead against his.
"…You're still mine," she said quietly.
Leo smiled. "Always."
Yuuko stood three feet away, frozen solid, face red enough to qualify as a fire hazard.
"…I–I'm sorry for existing in this moment."
Asagi looked at her.
Then sighed.
"…Okay. Logistics time."
Two hours later.
Fuuma Estate.
Main living room.
Ryuji sat on the couch, arms crossed.
Aoi stood beside him, holding tea.
Kotaro leaned against the wall, already sensing chaos.
Tokiko was eating chips.
Yuuko stood in the center of the room like she was on trial for war crimes.
Asagi stood beside Leo.
Ryuji stared at Yuuko.
"…So. You're a witch."
Yuuko bowed so hard her spine nearly snapped.
"Yes sir! I accidentally upgraded your son with eldritch magic sir!"
Ryuji blinked.
"…She's honest. I like her."
Aoi smiled politely. "Dear, focus."
Ryuji nodded.
"Right. Why are you here?"
Leo raised a hand. "Okay, before anyone freaks out—"
"She's moving in," Asagi said.
Dead silence.
Kotaro choked on air.
Tokiko dropped a chip.
Aoi's tea stopped halfway to her lips.
Ryuji slowly turned his head.
"…She what."
Yuuko bowed again. "I'm so sorry."
Leo rubbed his face.
"She has her own house. In the village. With electricity. And walls. And a perfectly good roof."
Asagi crossed her arms.
"And yet she summoned an eldritch entity inside a school classroom."
Yuuko squeaked. "It was a controlled ritual!"
Leo coughed. "It tried to eat her."
"…It was mostly controlled."
Ryuji leaned forward.
"So why does she need to live here?"
Leo gestured vaguely at himself.
"Because my body is now an eldritch Wi-Fi router."
Kotaro frowned. "…What."
Yuuko flipped open her spellbook nervously.
"The residual energy signature from my spell fused with his demonic taima structure. If his corruption destabilizes, it could backfire into an involuntary manifestation event."
Everyone stared at her.
She shrank.
"…He might grow more murder tentacles in his sleep."
Tokiko nodded. "Valid reason."
Ryuji pinched the bridge of his nose.
"So you're here to… what. Monitor him?"
Yuuko nodded rapidly.
"Stabilize his taima flow. Suppress eldritch resonance. Prevent reality tears. Minor things."
Leo pointed at her.
"She's also the only one who knows how to undo it if something goes wrong."
Aoi frowned slightly.
"…So you're basically his magical tech support."
Yuuko brightened.
"Yes! Exactly!"
Asagi stepped forward.
"And also," she added flatly,
"She's not safe living alone anymore."
Everyone looked at her.
Asagi's eyes hardened.
"Whatever she summoned. Whatever noticed her. It won't stop at one attempt."
Yuuko's fingers trembled.
Ryuji exhaled slowly.
"…Damn it."
Kotaro muttered, "Why is everything in this family cursed."
Ryuji stood.
"…Fine."
Yuuko's eyes widened.
"R–really?!"
"You can stay," he said. "Under conditions."
She nodded so fast it was a blur.
"No summoning. No rituals. No ancient demon contracts."
"Yes sir!"
"No seducing my son."
Yuuko short-circuited. "I–I wasn't—!"
Asagi cracked her knuckles.
"She definitely wasn't."
Leo swallowed. "Please don't kill her."
Ryuji continued.
"You report anything abnormal immediately. You sleep in the guest wing. You follow Asagi's rules."
Yuuko bowed again.
"I swear on my bloodline and my soul!"
Tokiko leaned toward Kotaro.
"…She's definitely joining the harem."
Kotaro sighed. "We're doomed."
---
Later – Guest Room Chaos
Yuuko stood in the guest room holding a single suitcase.
She looked around at the massive Fuuma estate.
"…I own a house."
Leo nodded. "Yes."
"…I pay rent."
"Yes."
"…I have furniture."
"Yes."
"…I am now living with my crush, his fiancée, his ninja parents, his cousins, and possibly several future demon girlfriends."
Leo gave her a thumbs up.
"Welcome to the Fuuma clan."
She sat on the bed.
"…My life derailed in six hours."
Leo smiled weakly.
"Same."
Later that night.
Asagi stood on the balcony.
Leo joined her.
"…You okay?" he asked.
She nodded.
"…I don't like it."
He winced.
"But," she added quietly,
"I trust you."
She looked at him.
"And if she's part of your disaster now… then she's part of mine too."
Leo took her hand.
"…You're still my priority."
She squeezed his fingers.
"…You better not grow a third girlfriend tomorrow."
He froze.
"…Define tomorrow."
She smacked his arm.
Elsewhere — The Demon Lord's Throne
A vast crimson hall stretched into darkness.
Black pillars carved with writhing runes lined the chamber.
Scarlet light pulsed through the floor like a slow heartbeat.
At the far end, upon a throne of obsidian and gold, sat a woman with legs crossed.
[Insert image of Astaroth.]
Her long red hair spilled over the armrest of her throne, past her waist.
Her yellow eyes glowed faintly in the gloom. Her big chest was there for people to see
She exhaled slowly.
"…Oh?"
Her eyes opened fully.
The air around her rippled.
She pressed two fingers lightly against her temple.
"…Now what is this new power I feel?"
A low hum rolled through the chamber.
Something distant.
Something wrong.
Something familiar in a way she didn't like.
Her long tongue slid briefly over one fang.
"…That resonance…"
She rose from her throne.
The floor cracked slightly beneath her heels as her aura expanded.
"This isn't Nomand."
She closed her eyes again.
The sensation sharpened.
Black.
Demonic.
But layered with something alien.
Something hungry.
"…Taima particles fused with… something else."
Her brows knit.
"…No. That's not a demon mark."
She laughed softly.
A slow, amused sound.
"…How interesting."
The heart tattoo on her chest pulsed faintly.
"…A human host… carrying an evolving eldritch strain… stabilized by demonic taima."
Her smile widened.
"…That shouldn't exist."
The shadows behind her twisted.
"…And yet it does."
She turned her gaze toward the mortal realm.
"…Fuuma clan."
Her eyes gleamed.
"…So that's where you are."
She licked her lips.
"…You're going to be a problem."
Then she chuckled.
"…Or a very entertaining investment."
She sat back down.
Crossed her legs again.
"…I'll let you grow."
Her fingers drummed against the throne.
"…Let's see what kind of monster you become on your own, Leo Fuuma."
Later that night, as Leo sleeped
Darkness.
Not empty darkness.
Thick darkness.
Like standing underwater with no pressure… no sound… no up or down.
Leo stood barefoot on a black glass floor that reflected nothing.
No sky.
No walls.
No horizon.
Just void.
He flexed his fingers.
"…Yeah. This is a dream."
The air shifted.
A woman's voice rolled through the space.
Low.
Smooth.
Warm.
"You belong to something bigger now."
Leo's jaw tightened.
"…Great. Cosmic voice. That's new."
The darkness pulsed faintly red.
"You are no longer just human.
No longer just demon.
No longer just taimanin."
Her voice circled him.
"You are becoming a convergence point."
Leo slowly turned in place.
"Show yourself."
A soft laugh echoed.
"No."
His eyes narrowed.
"You come into my head, talk like a final boss tutorial message, and won't even show your face?"
Silence.
Then—
"You will learn fear eventually."
Leo scoffed.
"Lady, I live in Gosha Village.
Fear is a daily event."
The darkness tightened.
"You absorbed something that does not belong to this world."
Leo folded his arms.
"It tried to eat my school. I disagreed."
A pause.
Then amusement.
"…You're already adapting."
Leo exhaled sharply.
"Look.
If you're gonna stalk my dreams, at least tell me your name."
Silence again.
The pressure increased.
"You are not ready for that name."
Leo's expression went flat.
"…Okay."
He raised his hand.
Then slowly lifted his middle finger toward the empty void.
"You know what I think, if you don't even wanna show yourself to me or tell me your name?"
The pressure spiked.
He didn't flinch.
"This."
He held the finger higher.
"Fuck off, lady."
The void went completely still.
Then—
A slow, dangerous chuckle.
"…You are going to be very fun to break."
Leo's eyes burned red for a second.
"Get in line."
The world cracked like glass.
Leo bolted upright in bed.
Breathing hard.
Sweat on his neck.
His heart pounded.
"…The hell was that."
He looked at his hands.
Normal.
No tentacles.
No blacklight.
No glow.
He rubbed his face.
"…Yeah.
Definitely not just a dream."
From deep inside him—
Something stirred.
Not Alex.
Not James.
Something new.
Something aware.
Leo lay back down slowly.
"…I'm gonna need therapy. Or a bigger sword."
To be continued
Hope people like this ch and give me power stones and enjoy and Leo harem is officially starting from this Ch