Became a Failed Experimental Subject-Chapter 41: Because of the Black Cat

“You didn’t press it by accident! This is why I told you to take a break from volunteer work—!”

[Nothing even happened thanks to that guy!]

The morning after the weekend chaos, Yu Anna, having just returned from escorting her younger sister, got the full report from the heroes who’d been assigned to her. Without a second thought, she called her little sister.

[And what, you think that’s something a hero should say? What about the people who’d starve if I wasn’t there?]

“I know, I get it, but it’s dangerous right now! There’s a villain named Gu Seoryong—”

[I know already. Can you drop it now?]

“I’m talking about your safety here!”

[Safety? Have you ever listened to me about anything? You kept doing hero work even when it was dangerous, climbed all the way to S-Class. And now this?]

“That’s not what this is abou—”

[Whatever. I have work to do. I’m hanging up.]

“Hello? Hey! Yu Hyena! Ugh, seriously!”

Click.

Yu Anna stared at the dropped call and sighed, leaning back into the couch, brow twitching.

“God... all this over one damn villain...”

Right now, a huge portion of W-City’s hero force had been reassigned to escort high-ranking officials and hero families.

After wiping out Guryong Fortress, the real cleanup had begun—clearing out the villains in Zone 9.

And with it came the rising fear of retaliation... and the ongoing pursuit of Gu Seoryong, who still hadn’t been caught.

Nothing had happened yet to the heroes themselves—but the fleeing villains had started lashing out at regular civilians.

Yes, they were being captured one by one. But “safe”? Not even close.

“Well... at least we’ve got Black Cat.”

“Hey.”

“...Haah.”

Yu Anna shot a sharp glare at the subordinate hero who’d said it—but sighed. Because it was true.

Without Black Cat, something would’ve gone wrong by now.

He was a disaster-class monster who had basically filled the gap left by all the reassigned heroes.

Running around W-City nonstop, 24/7, like an S-Class hero who never needed sleep—slaughtering monsters before anyone else even spotted them.

If not for him, monster-related damage would have exploded.

“You're right. Black Cat really is a blessing... Even if he’s a weird one.”

Heroes weren’t supposed to say things like that, but reality didn’t care.

In fact, within W-City, Black Cat’s danger rating had quietly been downgraded—no longer disaster-level, but calamity-level.

Whenever he appeared, heroes didn’t panic—they relaxed. Thank god he’s here.

The problem was... they weren’t the only ones thinking that way anymore.

Even the city’s higher-ups /N_o_v_e_l_i_g_h_t/ had started pulling the “Black Cat” card—

He’s already dealing with the monsters, so what are you heroes doing? Stop the villains at least! Escort us!

They’d never even fought on the frontlines, but their complaints weren’t wrong.

For now, the best option really was to leave the monsters to Black Cat and focus on minimizing villain damage.

Yu Anna had to find Gu Seoryong. Fast.

Before her sister got caught in her web.

“...Pull up the camera feed.”

“Right away.”

The assigned bodyguard handed her a small button device.

Yu Anna popped the chip out, plugged it into her phone, and replayed the timestamped footage.

And instantly, a familiar face appeared onscreen.

Wild, unkempt hair. Towering frame.

Muscles thick and symmetrical—not the kind you puff up at the gym, but natural.

“...That guy.”

Hard to forget a face like his.

The man who saved her sister was the same one they’d seen in Gu Seoryong’s bedroom.

Yu Anna pulled out a report—testimonies from villains captured at Guryong Fortress.

One line stood out: That day, Gu Seoryong took a man to her room...

His name?

“Park Dundeun...?”

That’s a real name? Seriously?

What kind of name is that?

Were the villains joking in their testimony?

No—this was cross-verified.

Was he one of her subordinates? Brainwashed by her abilities?

Trying to get close to Yu Hyena for a kidnapping?

If so, then that would’ve been the perfect moment.

But instead... he helped her.

None of it made sense.

Yu Anna narrowed her eyes and kept watching the footage.

And the longer she watched, the more tangled her thoughts became.

“Is he in the registry?”

“...Facial recognition came up empty.”

“He’s got at least top-tier B-Class, maybe low-tier A-Class physical enhancement. And not registered...”

Someone like that—strong enough to stand next to Gu Seoryong—should have been dangerous.

Maybe her subordinate. Maybe even her lover.

What the hell is he playing at?

Yu Anna scrubbed through every second of footage he appeared in.

And then—

[YARIKIRI!]

[WOOOOOO! YARIKIRI!]

She stopped the video with a sigh.

“...What the hell is this...”

“Maybe he’s just, uh... not all there?”

“Physically, he’s perfect. Fights like a monster. Total combat experience. But... mentally...”

“Like a giant child. That’s the vibe I get.”

“Either way, doesn’t seem like he’s here to cause trouble.”

If anything, maybe Gu Seoryong broke his brain.

Just a dumb musclehead with a pretty face and weird charisma—someone Gu Seoryong dragged to bed after drugging or brainwashing him.

Updat𝓮d from frёewebnoѵēl.com.

Feeling a little more at ease, Yu Anna made a decision and turned to the two heroes.

“Based on the footage, I really think he just comes here for the food. Try offering him a deal: if he stays in the park all day, from the start of distribution to the end, he can eat until he’s full.”

“You’re assigning him as your sister’s bodyguard?”

“He doesn’t seem dangerous.”

“...Should we try getting him hero-registered?”

“No. That would just paint a target on his back for other villains. Let him be. He doesn’t seem loyal to Gu Seoryong, and honestly... he’d make a great guard dog.”

If she could keep someone that powerful near her sister, then giving him food was a small price to pay.

Just then—

PIIIIIIIH!

Alarms blared throughout the government building where the heroes were stationed.

[Zone 6! Four calamity-class monsters detected! Repeating: four calamity-class monsters detected!]

That siren pattern—calamity-class.

The heroes instinctively jumped to their feet and rushed to the windows, ready to fly out.

But then the next broadcast stopped them mid-step.

[Continuing update: Black Cat sighted in Zone 6! Repeat, Black Cat sighted!]

“Ah.”

“Well. That’s fine then.”

“Fine?! It’s four of them! If even one gets away, the damage to the city—!”

“S-Sorry!”

Yu Anna had one foot on the windowsill, ready to leap out, but she stopped.

Then turned back into the room.

“I’ll go. Everyone else stay here. Monitor the area—if any villains use the alarm as cover, shut them down immediately.”

“Yes, ma’am!”

This should be fine, she thought, grabbing her gear and slinging it over her back.

From Zone 1 to Zone 6—W-City’s center to the outskirts—she made the flight in under a minute.

And there, flying through the sky in a blind panic, was one of the four calamity-class monsters.

Yu Anna barreled toward it like a missile.

“KYEEEEEK?!”

BOOM!

With a bloody explosion, she obliterated its lower body mid-air.

Landing hard on a rooftop, she raised a glowing, superheated fist toward the falling beast.

WHOOOOOOOM!

The fire-formed fist slammed into the monster’s remains.

Then she launched herself back into the air and caught what was left of its head.

“This is Starlight. One calamity-class monster neutralized. Type: Stormbird.”

CRUNCH.

Yu Anna crushed its skull between both hands and shattered the core, vaporizing it in flames.

Two hits. That’s all it took to bring down a calamity-class.

She could feel it—she was getting stronger.

Was it from chasing after Black Cat?

Flexing her fingers, she walked toward him. He was standing over another Stormbird corpse, foot planted on its neck.

“Grkk... grrk... grrk...”

“...Remaining monsters all neutralized by Black Cat.”

Stormbird corpses littered the area.

Black Cat had torn through three calamity-class monsters like they were snacks.

He hadn’t been like this the first time she saw him.

Now? He hunted them like they were low-tier threats. If he kept growing like this, he'd become extinction-class.

Would he still be her Black Cat then?

The thought alone gave her a strange sense of dread.

She spotted him chewing on another monster core—just munching away like candy—and stormed over.

WHAP!

Her unenhanced hand slapped the back of his head.

He didn’t flinch. Just kept chewing.

“Hey! Don’t eat that! Gross! Stop!”

“Kyaoo...”

“I’ll give you beef! Real beef!”

“...Mrr?”

Still gnawing on the core, Black Cat tilted his head and padded toward her.

Is this really a monster?

Devouring cores is how monsters grow—devour humans, devour monsters, and evolve.

But he was willing to ditch instinct for beef?

“Here. Drop it and eat this instead.”

“Mnyaaawnn.”

Yu Anna tossed him a grilled slab of beef and took the core from him, immediately destroying it with both hands.

He’d probably already eaten the cores from the other two, but this one she could still stop.

She sighed and dug through her bag, roasting slice after slice of beef and tossing them to him.

“It’s honestly a miracle you’re such a weirdo...”

“Waaonooo...”

“Tastes good?”

“Mrow.”

Watching him like this made all the planning worth it—filling her fridge, prepping the grill, buying out the market.

She smiled softly.

Then sighed again.

Should a hero really be doing this?

No matter how docile he acted... he was still a monster.

And yet—he helped her. Over and over again.

And because of that, a part of her couldn’t help but feel grateful.

“Haah... huh?”

Still tangled in her thoughts, she let out a sigh—and Black Cat suddenly rubbed his head against her leg.

“Wha—? H-Hey, are you... comforting me?”

“Mrow.”

“Oh, wait, no. You just want more beef, don’t you?”

Mouth wide open, drool gathering, eyes locked on the grill.

Yep. Thought so.

She grilled him another piece and handed it over—then hesitated.

If he’s letting me this close... maybe...

She slowly reached out toward his glossy fur, fingertips trembling.

Even as her hand brushed his soft, velvety head, he just kept eating.

Is this really happening?!

She gulped in anticipation.

And then—contact.

“Ah... ah....”

“Grrrrrrrr...”

He stayed still, gently rumbling, letting her pet him.

Yu Anna felt chills run down her spine.

All those videos she’d seen online, all those moments she secretly envied—

I'm petting Black Cat!!

“Kyaaaaaaaaaah!”

“Mrowr, nyaaaa! KyAAAAK!”

“Ah! Aaahhh!”

Her hands moved in frantic circles, tousling his fur.

Startled, Black Cat let out a strangled yowl and darted away into the shadows.

She stared at her fingers, shaking with regret.

“Ugh... I should’ve been gentle...”

She giggled anyway.

For the first time in days, the stress completely melted away.

****

“...So, if it’s alright with you, Mister Muryo, would you consider staying here on weekends?”

“And maybe even help out a bit with the volunteer work?”

The illusion of "Unlimited Free Refills" had died last week.

But despite that, I returned to the soup kitchen paradise, where two psychics now stood making me an offer.

Stay here during the weekend. Be around in case villains show up.

In exchange? I could eat as much as I wanted—just like my first day.

“Hmm. No thanks.”

I declined without hesitation and went back to eating.

That should’ve been the end of it, but they kept pestering me.

“W-Well, I know facing villains can be scary, but we’d be there with you. It wouldn’t be that much—”

“I’m busy.”

After eating, I need to nap.

I have to find new restaurants.

Sometimes I just need to roll around in the dirt by the riverside.

And they want me to give that up... to sit here smelling food I’m not allowed to eat?

What kind of twisted torture is this?

“...You don’t think the deal means you only get food if villains show up, do you?”

“Isn’t that it?”

“N-No... you get food either way—as long as you stay the whole time... until you’re full...?!?”

CLATTER.

I shoved my chair back and shot to my feet, grabbing my tray and shoveling the remaining food into my mouth.

Then I got right back in line and filled my tray to the brim.

Yu Hyena blinked at me in disbelief.

“...So that’s a yes?”

“Mm.”

“W-Well then... looking forward to working with you, Mister Muryo.”

I gave her a confident thumbs-up, basking in the pure joy of realizing that the dream—free, unlimited food—was real after all.

Even when clouds cover the sun... the sun is still there.

“You’re on par with Yarikiri. No—greater.”

“...Please don’t say that out loud.”

“From now on, I’ll call you Yarikiri.”

“I’m begging you, please don’t...”

Yarikiri... it’s a beautiful thing.