The Daemon Ninja -1-
Rewind time about six hours earlier, to the Forest of Beginnings.
"Haaah... Big bro... when the hell are ya comin' back already..."
In a spot where monsters no longer respawned, thinning out the adventurers' footsteps, a blonde girl with green eyes let out a sigh as she gazed at a gravestone. Etched on it wasn't the language of this world, Mundus, but Japanese: [Haku Yutakichi].
And standing before that grave was Park Seokgil's one and only friend, Tachibana Erika.
Her usual bubbly, scatterbrained, somewhat quirky vibe was nowhere to be seen. Instead, she wore a faintly sorrowful expression, her mood and face subdued low.
About a month had passed since Seokgil went missing and was essentially treated as dead by the Roman Empire.
'Big bro ain't dead... He'll show up again someday.'
But Erika didn't believe Seokgil was dead. Not only did she know him well enough to be certain he wasn't the culprit, but...
'Just like back then...'
In the past, when she was treated like trash kicked out by her family for her eccentric personality far removed from the norm, and bullied at school, she'd been walking with Ono Kanami when they crossed paths with thugs from the infamous delinquent school, Nishiyama High School. She'd nearly been raped.
-"It's fine. I've got you!!"
Seokgil had appeared out of nowhere in that instant, butchering the thugs right up to the brink of death.
-"Aaaah..."
And Erika and Kanami had fallen for him at first sight upon witnessing that.
Back then, Seokgil had been a promising star touted as the next national representative at school, so they hadn't crossed paths again. But when they hit third year, he inexplicably started getting bullied too, just like them. That shared misery let them grow close fast.
Sorry as it was to say about Seokgil, Erika was actually glad he'd been bullied—it gave her a chance to get near the guy she'd fallen for.
And through dating him and building that trust, Erika knew Seokgil was no one who could just die.
'Still... kinda miss ya and feel lonely, ya know...'
-Vmmm!!
As she murmured that, she raised the magic staff in her hand and cast a spell toward the gravestone.
A cleaning spell activated, polishing the stone spotless. As an Archmage, this was child's play for her.
"I worked my ass off to be useful to Big bro, ya know..."
Her power rank was two steps below black-grade, the pinnacle of humanity's indigo, and the highest among the isekai Hero party.
She had zero interest in studying so she didn't realize it herself, but she possessed a genius-level intellect unprecedented in this world.
Even so, without Seokgil around, Erika wasn't exactly thrilled.
"Haaah... Anyway, no clue when, but I'll come back next time, ya know."
As the top-ranked powerhouse, Erika had been thrown straight to the front lines.
She'd volunteered herself to grow stronger, too.
And lately, with the mushroom clouds at the front lines quieting the beast swarms, she'd finally had a breather to swing by here.
But who knew when the Demon King's army might strike again? No telling if she'd ever return to this spot.
Back on Earth, she'd have graduated high school by now and be a full adult, but she was still pining for one guy.
-Swish
As she placed a single flower on the gravestone and turned to leave—
-Clang!!
"Eek!?"
The sharp ring of metal clashing echoed, sparks flying as some metal object thudded nearby.
An ambush.
It wasn't that long, but as a front-line artillery mage bombarding the battlefield, Erika reacted on instinct.
-Vmmm!!
[Defensive Barrier]
[Arrow Block]
'Where the hell!?'
[Detection]
She deployed defensive magic instantly and fired off a detection spell.
A presence hit her senses.
"Over there, huh!!! [Fireball]!!"
-Whoosh!!
[Fireball]
She unleashed a probing spell straight at the presence.
-Boom!!
As flames erupted, she spotted the presence dodging the magic and shifting sideways.
And then—
-Shhrrk
"Hng... Guess a genius mage really is different, huh?"
Stealth dispelled like a chameleon's skin shifting colors, revealing the attacker: a woman in ninja garb, red glasses framing a stern, uptight face, gripping a kunai.
"You!?"
"Yeah, me..."
"Paper demon!!"
"I'm not!!"
It was Uehara Kotono, the student council president's secretary.
Erika hit her with one of her usual weird nicknames, but Kotono denied it vehemently, as always.
"Haaah, this is why trash spawn abandoned by their noble houses..."
"What the hell are ya doin' this for!?"
At the same time, Erika spotted the iron object that had been deflected earlier, now lying nearby.
A kunai.
The signature weapon of Kotono, the Roman Empire's near-sole possessor of the Ninja class.
No doubt about it.
So as she hurled the question, she prepped her magic.
"Why?"
Kotono answered with an irritated scowl.
"'Cause you piss me off, obviously."
"???"
For a moment, even Erika's fourth-dimensional brain couldn't parse Kotono's words.
Piss her off? She and Kotono barely had any interactions to begin with. What the hell could be pissing her off?
And Kotono's follow-up blew past even Erika's quirky common sense.
"It ticks me off. How a discarded inferior from your clan builds more fame than the exalted scions of the great Minamoto house... Super annoying."
"Haaah?"
"So I'm gonna erase you and put them at the center of this isekai world. Disappear already."
"You fucking lunatic!!"
Erika sensed it. The psycho meant every word.
Kotono's eyes gleamed with fanatic loyalty bordering on zealotry.
As a vassal house to the Minamoto, raised from birth for the role of his aide with near-brainwashing education, Kotono's mind was worlds apart from normal.
Her urges had been suppressed by weakness before, but now with power, she was spiraling out of control.
Acting on her own to make her master the greatest.
"If that's what ya want, I'll K.O. your ass!!"
-Vmmm!!
Mana surged from her body.
"Hah!! You got trained, so you know damn well—in a mage-assassin fight at this range, who wins?"
"Like that matters, ya know!!? Big bro said it!! Firepower knows the answer!!"
"Hmph!! Figures a weakling visiting loser's graves wouldn't get it."
-Snicker snicker
Her mocking sneer and the jab at Erika's sore spot ignited the greatest rage she'd ever felt—not even the adults back home calling her useless compared.
"Big bro ain't dead!! You paper demon bitch!!"
-Grind
-Vwooom!!
Erika gnashed her teeth, mana exploding from her fiercer than before.
The air around them shifted.
"Haaah... Fine, whatever, you've got skills at least. Blocking my kunai earlier and all. Worked pretty hard on that one."
-Clack
Kotono raised her own kunai, battle-ready.
As tension crackled between them, Erika spoke first.
"Lemme correct ya. I didn't block your kunai, ya know. Your aim sucked, ya threw it wrong, and now you're blamin' me."
In truth, Erika hadn't cast a thing. Totally defenseless.
"Haaah? What're you... Then what the hell blocked my kunai..."
Kotono's sneering words cut off abruptly.
Her eyes and mouth flew wide in shock.
And her face twisted into the expression only those gripped by inexpressible terror could wear.
"Wha... wha-wha?"
A panicked, terrified voice leaked from Kotono.
Her gaze fixed on Erika's back.
-Vmmm!!
Erika felt a pale, sunken light suddenly thickening behind her.
She first thought it was her own mana glow, but Kotono's reaction told her otherwise.
"What the hell are ya starin' at...?"
Turning with the question—
"Eh?"
-Grooooowl
Behind her stood a being watching over her like a guardian.
Undeniably not human.
A massive, pale, translucent figure at least four meters tall loomed there.
"Uwaaaah..."
"Uaaaaah..."
"Uwaaaah..."
Dozens of translucent heads groaned in agony, their chorus forming an eerie quartet.
And two enormous, translucent arms—like giant demon hands—enveloped her protectively.
"..."
Unlike the screaming horde, the largest head stared down at Erika with chilling emptiness.
"O... Ooooh..."
Erika, in fear, opened her mouth to scream—
"It's so coooool!!!"
—but instead, her eyes sparkled like a kid spotting an awesome robot as she gazed at her protector, [Phantom].
-Twinkle twinkle
Her starry-eyed gaze beamed at Phantom.
Forget not: she wasn't casually fourth-dimensional.
She'd been obsessed with the occult in elementary school, even sneaking to a graveyard at midnight to see ghosts.
She lost interest quick, sure, but her aesthetic sense was anything but normal.
No wonder she clicked with Park Seokgil.
-Smirk
Phantom's hollow face cracked a faint smile.
And then—
-Shhrrk
"Eek!? Somethin' feels off, ya know!?"
The spectral Phantom phased straight through Erika, stepping forward as if to shield her.
"Wha-wha-wha-what the hell is that!?"
-Shwick!!
Terror-struck and stammering, Kotono hurled a mana-infused kunai at Phantom's head.
But—
-Squelch
"N-No way!! It went through!? Mana on a weapon should've wrecked a ghost beast like that...!?"
The kunai passed clean through Phantom's head.
As she'd said, a low undead would've been toast, but unfortunately, Phantom was high-grade.
To hit it proper needed [Spirit Strike], [Essence Strike], divine power, or the like.
"Kekekekeke!!"
"Hohohohoho!!"
"Hehehehehe!!"
"Hahahahaha!!"
"Uuhehehehe!!"
The dozens of heads, once groaning in pain, erupted in unison with ghastly, mad laughter.
Old man, woman, child, burly man—disparate voices blending into a profane symphony that could drive a human insane just from hearing.
"Hiiiik!!!"
Kotono bolted to flee in horror—but
"..."
"Wha... wha-wha..."
Behind her, as she turned to run, stood Phantom—mere seconds ago in front of her.
"Hi, hiii...!!"
Kotono's brain refused the reality at first, but as it sank in, she drew breath to scream in terror—
-Grab!!
"Guhk!?"
One of the countless evil spirits comprising Phantom's body seized Kotono's throat.