I Sealed Sukuna’s Finger#407+408: Let Me Help You Get Stronger, Bathhouse Party

Time rewind to three minutes earlier, at the top of Keystone Gate, in Nagisa Akatsuki's home.

"Good night then, Yukina-chan. I should be heading to bed too."

In the apartment bedroom, after exchanging good nights over voice chat with her friend just a wall away, the True Ancestor girl—already showered and in pajamas—tapped the end call button on her phone screen.

Beep.

Seeing "Call Ended" appear on the screen, Nagisa sat at her desk and couldn't help covering her mouth for a small yawn.

It really was getting late—almost eleven o'clock. Time for bed.

But then again...

Like someone with a growling stomach debating whether to indulge in a late-night snack, Nagisa unconsciously placed her hand on her belly and rubbed it gently.

Come to think of it, she hadn't had a chance to do anything with Big Brother these past two days. Her stomach felt so empty—she wasn't used to this at all.

Wonder if they could find time tomorrow...

With that thought, the ready-for-bed Nagisa rose from her desk and turned to close the bedroom window that faced outside, planning to draw the curtains as well.

But the instant her small hand touched the window frame, a figure walking toward the old school building nearby caught the girl's attention.

Huh? Wasn't that Big Brother? And beside him seemed to be... Kuroka? Were they going to Rias's place?

But at Rias's place right now...

Nagisa looked toward the old school building again. In the twilight, the first floor lights were completely off, and only two or three bedroom lights remained on upstairs.

Though she had no concrete evidence, going over at this hour could only mean one thing.

They were definitely having a party!

At this realization, Nagisa's eyes instantly hardened with determination.

How dare they have a party without telling Nagisa! This wouldn't do at all!

Thanks to the recent situation with Asagi, Nagisa had completely figured things out.

Constantly yielding would only make her miss opportunities. Like how she'd acted like such a good girl in front of Asagi to avoid causing Big Brother trouble, never daring to overstep—only to watch Asagi and Big Brother be affectionate in public.

Now that everyone had moved in together, if this continued, her chances with Big Brother would only decrease.

Nagisa absolutely wouldn't allow that!

She had to take the initiative!

So first, change clothes...

With that thought, Nagisa stepped back from the window and walked to the closet on the other side, pulling out a school swimsuit.

That's right—no need for fancy, sexy outfits. Nagisa just needed to stay innocent and cute, then pull aside that small piece of fabric in front of Big Brother~

❁❁❁❁

Scene shift to the old school building's bathroom.

Gasper, who'd thought it was his turn to bathe but found people still inside, stood frozen at the door.

The sliding door behind him was already closed. To leave, he'd have to open it again, while sounds continued from deeper in the bathroom.

"Mmm... Bokue, you're amazing! Big sis is going to... ngh!!!"

Gasper couldn't understand what they were saying—it was all disjointed nonsense—but he could hear the intense emotion in it.

Though it sounded like pleading, for some reason Gasper felt that Koneko's sister in the bath... seemed happy?

It was contradictory.

Since the old school building's bathroom connected the toilet area to the bathing area—sliding door first led to the sink and toilet, with the actual cypress-lined bath through a door on the toilet's left side—Gasper standing at the entrance couldn't see what was happening inside.

He felt... somewhat curious to investigate?

For the first time ever, the normally shy, socially anxious blonde vampire boy had such a thought.

But the next second, he crushed it himself.

Wh-what was he even thinking?!

Hearing that Kuroka sister crying out so intensely, obviously nothing good was happening in there.

Especially since his Evil Eye couldn't even stop the other person—what if he got caught peeking and punished too?

No no no, absolutely—NOT!

With that thought, Gasper was already considering retreat.

He'd figured out his next move.

Either pretend he knew nothing and quietly leave the bathroom—skip bathing today.

Or go upstairs to find Koneko, tell her that her sister was being bullied in the downstairs bathroom by President Rias's boyfriend...

"Oh? Is that Gasper-kun?"

Just then, a familiar girl's soft voice came from above.

Eek!!!

Completely unprepared to be discovered at such a moment, Gasper—still crouched in his box—nearly jumped straight up. His "time-stopping Evil Eye" instantly activated.

But it was useless.

The True Ancestor girl appearing above his box, just like Bokue Keikain, was completely unaffected by his time-stop ability. She peeked down directly, her delicate face visible through the cardboard hole to Gasper's eyes.

"Eh? You're... Lady Fourth Progenitor..."

"No need to be so formal. Just call me Nagisa."

Nagisa smiled and jumped down from the box, putting a finger to her lips in a shushing gesture.

"Gasper-kun came to bathe too, right? Then you found Big Brother and Kuroka doing strange things inside, so you're hesitating whether to go in, right?"

"...Yeah."

Perhaps trusting this True Ancestor girl who seemed his age but felt completely different from any other vampire he'd met, Gasper softly agreed.

"Just as I thought."

Nagisa's lips curved in an "as expected" smile.

"But Gasper-kun doesn't need to be afraid. Big Brother is very gentle. What's happening in the bath right now is Big Brother working hard to help Kuroka get stronger. How should I put it... it's like exercise. Though it's tough, there are many positive gains afterward... Oh, has Gasper-kun tried training before?"

"...I have."

Gasper nodded again.

He felt he could roughly understand what was happening inside now. After all, he'd once worked hard trying to control his Sacred Gear's power, but ultimately had to give up and become a shut-in when results were minimal.

But he could understand gaining results through hard work.

"That's wonderful then."

Nagisa continued coaxing.

<><><><><><><><>

“Meow… meow…”

The bath echoed with soft feline whimpers.

The first round was over, and the cat-eared girl who had started the night brimming with confidence—vowing she’d make Bokue beg for mercy—was already reduced to a melted mess.

Bokue Keikain leaned back against the steps inside the bath, warm water lapping up to his chest.

Clinging to him face-to-face was Kuroka. Her flushed cheeks pressed against his shoulder, arms looped around his neck, her voice trembling as she rubbed against him with spoiled affection.

Her mind was clearly swimming in pink bubbles.

After all, a nekomata was still a cat—and cats weren’t exactly built for stamina. She couldn’t last long in a single stretch before throwing up the white flag.

Bokue honestly hadn’t expected her to give up in under five minutes. Usually she could hold on for at least ten before tapping out. But this time, the month-long drought must have worn her down. Barely had they started, and she was already done.

As he thought this, the black-haired, cat-eared girl suddenly tilted her head up, pouting.

“Hawaw… bad…”

“…?”

Bokue blinked, confused. Already calling him “bad”? That was supposed to come after everything was finished, when she was sprawled out mumbling nonsense in the “post-match delirium” phase.

“What’s that supposed to mean, nya? Don’t tell me you won’t even admit it?”

Seeing his puzzled look, Kuroka puffed her cheeks and pushed further.

“It’s been nearly a month since we last met. That doesn’t even average out to once every three days. You really expect me to believe you were that well-behaved? Be honest—haven’t you been wearing out that blonde human girl on Itogami every single day, nya?”

“How could I…”

Bokue spread his hands.

Not that he couldn’t handle “every day till dawn.” But Asagi—certainly couldn’t. Even with his magnetic field power restoring her stamina and repairing her body, the mind wasn’t so quick to recover.

Like this afternoon—six hours straight. She’d need at least three days to bounce back.

If they really went at it daily, her health wouldn’t collapse… but the side effects on her body might become irreversible. Give it long enough, and one casual touch from him would set off golden champagne fountains.

That wouldn’t do.

“Hmph… fair point, nya. That human girl looks like a total shut-in anyway, soft and out of shape. No way she could survive you cutting loose.”

Kuroka muttered, then narrowed her eyes thoughtfully.

“Then… it must’ve been that little True Ancestor. Back in the Underworld, I heard vampires recover insanely fast. If she’s a True Ancestor, she might heal even quicker than that phoenix clan. Even shredded to mince, she’d regenerate in seconds. With that body, you could pound her all you wanted and she’d never break.”

“…”

Bokue fell silent.

Women’s intuition?

A minute ago she’d been babbling nonsense, and now she’d hit the bullseye—perfectly.

Genius masked as foolishness? Or just a blind cat catching the canary?

“Hmm? Why so quiet?”

Kuroka lifted her face, eyes narrowing.

“Don’t tell me… I guessed right, nya?”

“…”

“…That’s exactly right.”

A bright voice cut in from just beyond the wall.

Wait—that voice—

Bokue’s chest tightened. Kuroka’s ears shot up as she whipped her head toward the door.

The next second, Nagisa stepped into the bathhouse, bare feet padding softly on the tile, her school swimsuit clinging to her petite frame. She smiled brightly, tilting her head in mock innocence.

“Sister Kuroka was spot-on. For the past month, I’ve been deepening my bond with big brother every single day. He always spoils me with so much to eat… feeding me and feeding me until I can’t take another bite.”

“W-what?!”

Kuroka’s blood pressure spiked. She shot upright—only to stiffen as the motion set off a violent ripple in her stomach, forcing her back down with a strangled groan.

Nagisa giggled behind her hand.

“Hehehe… looks like big brother’s been feeding you plenty too, Sister Kuroka.”

Ignoring the catgirl’s glare, she waded into the water, moving right up to Bokue’s side.

“Well then… since Sister Kuroka seems tired, she can take a break. Big brother, now it’s my turn—”

“Don’t even think about it.”

Kuroka hissed like a cat guarding its food, clinging to Bokue with arms and legs both. It was like watching a gamer hogging the arcade cabinet—dead, but refusing to let go of the joystick.

“Enough. Since you’re both here, we’ll do it this way.”

Bokue pinched the bridge of his nose, resigned.

“Kuroka gets another round. After that, it’s Nagisa’s turn. One at a time, alternating.”

“Ehh? But then I’ll have to wait again…”

Nagisa pouted, hugging his arm.

“I can’t hold back much longer.”

“Don’t worry. You won’t be left idle.”

Bokue raised a finger. Golden light shimmered, expanding outward to envelop the entire bathhouse—steam, tiles, even the outer washroom.

Nagisa gasped, pressing a hand to her stomach beneath the swimsuit.

“Huh? This feeling… is this shared sensation?”

“Shared sensation—and equal distribution.”

Bokue nodded.

“Yuuma showed me twice before. It seemed convenient, so I picked it up. I haven’t used it much yet, but… it works well enough.”

In truth, this was only his second time.

The first had been in the Underworld—when Lady Venelana and Grayfia had joined him in the bath. With this technique, he’d carried them both to the peak at once.

“I see… so that’s how it is.”

Nagisa’s voice quickened, her breaths coming faster.

“It’s not the same as being with big brother directly… but this is still pretty nice… mmm…”

“Then let’s test it properly.”

The moment Bokue spoke, Kuroka’s body began moving again in the water—