How Shall I Screw Him Over?

After skimming the news, I downed the now-cold coffee in one gulp.
"Haa...."
The warm sunlight streaming through the window and the bustling street full of people looked like any ordinary scene in Korea, but I'd reached one clear conclusion.
I'd been possessed, as they say.
My original identity and appearance as Kang Jinwoo seemed intact, but I'd been dropped into a world where villains caused mayhem and heroes flew through the sky blasting beams.
"...That bastard Tanaka-kun."
A curse slipped quietly from my lips.
Throwing a reader who fact-checked the flaws in his novel into the story itself? What kind of bullshit was this? And what the hell was Tanaka-kun's deal anyway? All I knew was that the guy was a die-hard hentai otaku, steeped to the bone in twisted ideologies.
Because of that rotten personality, his so-called transformation webnovel had South Korea wiped out right from the prologue. And of all places, I'd landed smack in the doomed Korea.
Forget returning to my original world for now—even if I stayed put, my future was either death or becoming a refugee like in the original story.
"Hah, that fucking Tanaka-kun...."
I let out yet another sigh laced with curses and reorganized the situation.
I, Kang Jinwoo, had been possessed into the novel written by that asshole Tanaka-kun, dropped into a Korea that would be destroyed in three years by the so-called Absolute Evil villain.
But I had an ace up my sleeve: the original story knowledge I'd grudgingly gained by slogging through that trash novel to the end.
I could use that to build wealth, flee abroad, live comfortably without a care—but—
"Hah, don't make me laugh."
Sure, I could save my own skin with the original knowledge, but that meant letting the story play out as is. Exactly as that bastard Tanaka wanted.
The thought of dancing to the tune of the prick who'd arbitrarily shoved me into his novel just for critiquing it made my stomach churn, even though I hadn't eaten.
"You think I'd let that happen?"
One thing I knew for sure: I wasn't giving Tanaka-kun the satisfaction, not even in death.
"I'll smash it to pieces. I'll turn your precious original story into a total mess!"
"H-Hiiik! S-Sir...! P-Please calm down...!"
The scream jolted me upright. The cafe employee was trembling like a leaf, clutching her tray.
Apparently, I'd gotten too immersed in my revenge fantasies against the author.
"Ah, ahem. Sorry about that. I got a bit worked up. And I'll have another Americano here."
Embarrassed, I cleared my throat and handed over my card. I'd been sitting a while, so I ordered anew as a seat fee, but the employee still eyed me warily as she processed it.
No wonder—glancing in the mirror, this guy's harsh features screamed villain. If he wasn't mistaken for one, it'd be a miracle. My looks weren't great back home either, but here or there, this face invited misunderstandings. I sighed involuntarily.
Soon, I took the fresh coffee from the employee and sat back down to revise my strategy.
Survival was secondary now. My sole goal: shove a massive prickly surprise right up Tanaka-kun's ass.
How could I twist that hack's guts? Kill the protagonist? Nah, amateur hour. Besides, the guy's guarded by his world's top-tier brocon big sis—impractical as hell. More importantly, offing one protag wouldn't change the Korea-dooming scenario.
A guy as Japan-obsessed as Tanaka wouldn't care much even if Korea fell, as long as the protag died.
Hand the villains original knowledge to wipe Japan first? No, those bastards wouldn't stop there.
Truth be told, I didn't give a damn about Tanaka-kun's world, but no guarantee I'd be back home by then. No point getting dragged into the mess.
So, table that for now.
Last option: hog all the original story's lucky breaks, become a hero, and stop the Absolute Evil myself.
"...Ugh, no way."
Just imagining it gave me chills all over. Strutting in skintight spandex like the hero on the news, spouting cringey lines like "For justice!" or "For the citizens!"? Not my style, not ever.
Damn it, how the hell do I serve up a big one to Tanaka-kun?
Join the villains and spill all the intel? Guarantee my safety in the deal?
I was wetting my lips with that thought when—
Boom!
A sudden impact rocked the building hard. Coffee spilled across the table, soaking my pants, but I barely registered the heat.
Screams erupted from employees and customers alike.
"Wh-What the hell?!"
I peered out the window, doubting my eyes.
A car was literally flying through the air.
A car?
Too late to process. The massive hunk of metal shattered the glass and crashed into the cafe.
"KyaAaAaK!"
Shards and dust blinded me. Realizing the car had whizzed right past where I'd been sitting, my strength drained, legs buckling as I collapsed to the floor.
Trembling, I exhaled shakily.
"Wh-What the fuck kind of lightning bolt out of nowhere...."
"Villain! A villain's appeared!"
Desperate screams from outside drew my gaze. The once-peaceful street had turned into hell.
Amid shattered sidewalks and burning cars loomed a hulking man in a tiger mask.
Muscular build like a wrestler, he smashed and hurled everything in reach, clearly unhinged.
"GRRAAAH! I'll smash it all!"
Roaring like he had anger management issues, he lifted a truck one-handed. Not just crazy—this was a disaster, pure terror incarnate.
Zzzzt!
"Hup!"
Instinct kicked in; I ducked behind the wall.
Had that maniac locked eyes with me? Tanaka-kun wasn't that heartless—I had two powers too—but they weren't suited for combat. Facing that monster head-on? I'd be paste.
Please, just go. Pass by, please....
But this cursed world had no intention of granting wishes.
Crunch!
"There you are!"
A massive, crude hand punched through the wall like paper and snatched my collar.
"Gurk!"
Dangling in midair, I met his eyes. Bloodshot, gleaming with madness.
"You called me Muscle Pig too, didn't you?"
When the hell did I?! I wanted to scream, but my throat only gurgled.
"I like being Muscle Pig. 'Cause I love muscles. But anyone who calls me pig—I'll kill 'em all!!"
His grip tightened, vision flashing white, consciousness fading.
As death loomed, injustice surged.
Damn it... Haven't done shit yet, haven't even screwed over Tanaka once...!
I was closing my eyes in vain when—
"That's far enough, villain!"
"Grk!"
A sharp impact, and the chokehold vanished. I flopped to the floor, gulping air instinctively.
"Cough! Cough! Hah, haaah...!"
Coughing till tears welled, I looked up.
A petite girl with fluttering brown hair stood there.
"Are you okay? Any injuries?"
Her worried eyes scanned me, voice young yet firm.
"I-I'm fine, fine."
Neck nearly snapped, but no injuries—lucky, I guess.
She nodded in relief.
"Good. That's a relief."
She turned sharply to the staggering villain.
"I'll handle things here. Hurry and get out while you can."
"O-Okay. Got it."
Plain-looking unlike flashy news heroes, but the hero suit marked her as one. Face-obscuring tech hid her features, but she was way smaller than me. Voice sounded a bit childish too—minor?
Nah, even with hero shortages, they wouldn't deploy kids—wait, the original protag was a minor too, right? Was she...?
"GRRAAK! You puny brat dare?!"
"Watch out—get back!"
"Aigoo, sorry!"
The enraged villain rampaged anew; she shouted urgently. Better bail—no good getting tangled.
Confirming I'd retreated safely, she declared boldly at the villain.

What? What did she just say?
The name hitting my ears was both alien and familiar.
Nova? If it's Nova, then definitely...
If memory served, it was the name of a Korean-origin villain from early in the novel.
Come to think of it, that villain Nova had brown hair too. Was this her?