Chapter 71: Side Story - Issei’s Transformation!?

[Rias Side]

"Mm… morning…"

The morning sunlight streaming through the window woke me. Sitting up in bed, I saw the usual scene: all the Occult Research Club members, packed together, sleeping in the same bed.

It was two days after Kuoh Academy's sports festival, following the ordeal with the Old Demon King faction.

Asia returned safely, and Issei, who fought fiercely against the Old Demon King's descendants, came back alive. I was truly relieved.

But…

My gaze drifted to Issei's right arm. A vivid burn scar. He didn't talk much about it, but it's believed to be from the greatsword he used.

I felt pathetic. As Issei's master, I'm supposed to protect him, yet I'm always the one protected—during Raiser's incident, Kokabiel's, and now this. I keep burdening him.

I'm a failure as a king.

Still, Issei would never blame me. He's too kind.

But I can't lean on that kindness forever. I need to get stronger—much stronger.

I gently stroked his sleeping cheek. "Issei… I'll become strong. A king worthy of you."

That's when it happened. The room brightened faintly.

"—What?"

The glow came from Issei. With a faint groan, his body began to change—from a sturdy young man to a small child's form.

…

...

...What?

I froze, my mind unable to process as Issei shrank before my eyes, stopping at a size smaller than Koneko. He looked just like the childhood photos his mother once showed me.

What's happening…?

My thoughts stalled, overwhelmed by the impossible sight.

"Mmm…" Issei, now a child, slowly sat up, rubbing sleepy eyes. He glanced around, meeting my gaze.

"Uh… Issei…?" I stammered, unsure how to address him.

He blinked at me and said, "Onee-chan… who are you?"

[Rias Side Out][Kiba Side]

Early that morning, the Occult Research Club and Azazel-sensei gathered at Issei's house. His parents were away on a hot spring trip, won by lottery.

Everyone's faces were serious. Rias had called an emergency meeting, and the cause was the childlike Issei, sitting bewildered on her lap.

Why did this happen?

Yesterday, he was fine, running with Asia at the sports festival. I spoke to him, and aside from exhaustion, he seemed normal.

What caused this?

Azazel-sensei turned to Koneko. "Koneko, how's his condition?"

"I checked," she said. "His energy flow is stable, but…"

"But?" Azazel prompted.

"His energy volume is significantly lower."

Lower energy? What does that mean?

Koneko explained, "Issei-senpai taught me that living beings need a certain amount of energy to maintain their bodies."

"So," Azazel said, stroking his chin, "Issei overused his energy in that fight, and the effects are showing now."

Overusing energy to that extent? Was he that reckless?

Koneko nodded. "Normally, beings can't manipulate energy unless trained in senjutsu, like me, or special combat skills, like Issei-senpai. The body unconsciously absorbs and circulates enough energy, so physical changes don't occur. But…"

Issei's lack of sufficient energy caused his current state.

Azazel sighed. "I want to scold him for pushing himself, but this is my fault. I anticipated Old Beelzebub and Asmodeus might target Rias but didn't send enough forces. Ddraig, how's Issei's mental state?"

A jewel appeared on Issei's left hand. [It's relatively calm, but his shrunken body has regressed his mind to a childlike state, with memory loss.]

Memory loss too…?

[Don't blame yourselves,] Ddraig said. [This happened because it was his first time in that form, facing demon king-class foes, and using that sword. Multiple factors converged. He wouldn't want you to feel guilty.]

Ddraig's words didn't ease the guilt.

Azazel sighed again. "We need to restore him, but I've never seen this before. Rias, I'll check with my contacts. Try something on your end."

With that, he vanished through a teleportation circle.

After Azazel left, we racked our brains. Issei didn't remember our names, so we reintroduced ourselves, but what could we do?

Our gazes fell on the now-adorable Issei, tilting his head innocently. The girls were struck hard.

"So… cute," they chorused.

Even I found him adorable, a stark contrast to his usual boldness.

"Hmm, this young Issei is… quite nice," Xenovia said.

"Totally," Reynare agreed. "He's usually cool, minus the pervy side. This is a shock." Reynare, you're drooling…

I turned to Rias. "What do we do?"

"Let's think of solutions," she said. "Any ideas?"

Akeno raised her hand. "What about restoring his memories?"

All eyes turned to her. Brilliant.

"Nice, Akeno!" Rias beamed. "If his memories return, he might know a way out!"

Issei's knack for energy manipulation could hold the key.

"How do we do that?" I asked.

Akeno smirked. "Easy. Issei loves one thing—boobs."

…

The plan to restore Issei's memories began with Akeno's bold suggestion.

[Rias Side]

Akeno's idea sparked the memory restoration plan. Sure, Issei loves women's chests, but… would that really work?

Kiba and Gasper were sent to the Underworld to research other methods, but if Azazel hadn't seen this before, their chances seemed slim.

"Akeno, I get it, but what's the plan?" I asked.

"We strip and let Issei touch us," she said.

!?

Everyone froze, wide-eyed.

"Are you serious!?" I exclaimed.

"Absolutely," Akeno replied. "Stimulating him with what he loves might trigger something."

Stimulation… maybe the wrong kind, but it made some sense. Worth a try.

"Alright, let's strip," I said.

"Really!?" Irina gasped, angelic sensibilities shocked.

"No pressure," I added. "It's not guaranteed."

"Ugh, for Issei…" Irina mumbled.

Xenovia stepped forward. "No issue. If nudity restores him, it's a small price."

She shed her clothes boldly. Typical Xenovia.

"I-I'll do it too!" Asia said.

"Me too!" Miu followed.

Their devotion to Issei was intense. I couldn't fall behind.

Minutes later, everyone but Issei was in underwear. Even Irina joined to help.

Normally, Issei would be nosebleeding with joy, but now he just stared, puzzled, like, "What's going on?" At four or five years old, his lack of reaction was understandable.

"Oh my, this is tricky," Akeno said. "Issei-kun…"

She moved to let him touch her, but—

"What, Akeno-onee-chan?" he said.

!

Akeno froze, blushing and grinning. "Akeno… onee-chan… what a lovely sound."

"Akeno, you okay?" I asked.

"Rias, have him call you that," she urged. "You'll understand."

I looked at Issei, who met my gaze with a curious tilt. "Uh, Issei?"

"What's up, Rias-onee-chan?"

!

A jolt ran through me. This feeling… my heart swelled.

I grabbed Akeno's hand. "I get it now!"

"Right!?" she exclaimed.

This overwhelming warmth… I hadn't noticed earlier in the shock, but…

"W-What's with you two?" Asia asked, confused.

"Talk to him, Asia," I said, grinning.

"Um… Issei-san?" she ventured.

"Asia-onee-chan?" he replied.

"Hau…!" Asia melted. She got it—the freshness, the joy, the thrill of being called "onee-chan" by a tiny Issei. His cuteness was devastating.

We were done for. That bold Issei, now this adorable? Irresistible.

One by one, the others called his name, got "onee-chan" in return, and melted, forgetting our original goal.

Hours later, a cute growl came from Issei's stomach.

"Hungry…" he said, clutching his belly.

The clock read just before 1 p.m. We'd been so caught up, we forgot lunch.

"Let's pause for lunch," I suggested.

"Sounds good," Miu said. "Onii-chan's at his limit. What's on the menu?"

"Something quick… spaghetti?" I proposed.

So, we made meat spaghetti. After changing back into clothes, we cooked. Issei's face lit up when it was ready, every gesture painfully cute. Everyone mirrored my expression.

Then, Issei frowned, struggling. "What's wrong?" I asked.

"Can't eat right…"

We realized his scarred right arm, still unhealed in his child form, made eating difficult. He'd tried alone, dropping spaghetti on his clothes.

"Sorry…" he mumbled, looking crestfallen.

I gently patted his head. "It's okay, Issei. I should've considered your arm. Let's clean you up, and I'll feed you. Rely on us, okay?"

He always saves us. This is the least we can do. I want him to lean on us more—I truly mean it.

"Thanks, Rias-onee-chan."

Post-lunch, we tried various methods. Akeno's plan—letting him touch our chests, showing his favorite risqué books and videos—yielded no results. Koneko's senjutsu to improve energy flow changed nothing. Time just slipped by.

Now, bath time.

"Stay still, I'm washing you," Miu said.

"Okay!" Issei chirped.

A debate over who'd wash him led to rock-paper-scissors; Miu won. She pumped body soap, lathered her hands, and gently washed him, mindful of his delicate child's body.

Issei squirmed, ticklish, but Miu teased, "Hold still!" and kept scrubbing.

"Fufu, so heartwarming," Akeno said.

"Like real siblings," I agreed. "Though they're always close."

"They are," Asia added.

"Koneko-onee-chan… Koneko-onee-chan," Issei mumbled.

Koneko beamed, thrilled by the title since noon.

"All clean!" Miu announced, turning off the shower.

Issei grinned. "Thanks, Miu-onee-chan!"

!

Miu froze. Beyond his cuteness, being the "little sister" usually, this was new. "Too cute!" she cried, hugging him tightly.

I understood. I wouldn't resist either.

"Eek!" Miu yelped.

I looked over—Issei was suckling her chest.

"Issei!?" I called, but he was too engrossed.

"Hey, Issei-kun!" Reynare grabbed his shoulder. "You're troubling onee-chan!"

Issei spun, lunging at Reynare. "Eek!"

"You okay?" Xenovia asked.

"I'm fine, but—ah! Issei-kun!?" Reynare gasped, now his target.

"No… stop…" she moaned, lost in ecstasy.

He'd never been this intense, even with his love for chests. Why now?

"What's happening?" Xenovia asked.

"I don't know," I said. "We should help Reynare."

Her blissful expression suggested otherwise, but…

"Wait, Buchou!" Koneko interrupted.

"What?"

"Issei-senpai's energy is increasing."

!?

Everyone gasped. Increasing energy?

"He's trying to return to normal?" I asked.

"Likely absorbing energy from… chests," Koneko said.

"So, letting him do this restores him?" Akeno clarified.

Absurd, but plausible, given his rising energy. Was it instinct?

There was only one thing to do. "Everyone, offer your chests to Issei!"

I couldn't believe my own order, but if there was a chance…

"Got it!" Xenovia said. "Reynare, my turn!"

"Xenovia-san…?" Reynare mumbled.

"Issei! My chest—whoa!" He pounced, knocking Xenovia down. She avoided hitting her head, thankfully.

"Ow… Issei, slow down! Ah… oh…" Xenovia sighed sweetly.

"Rias-oneesama," Asia said. "Is this okay? My… chest is… smaller than everyone's…"

"Mine too…" Koneko added, clutching hers.

They weren't as endowed, but it should be fine, right?

One by one, we all offered our chests.

[Issei Side]

Ugh…?

Where am I?

I was exhausted yesterday and crashed… but this isn't my room.

Steam filled my vision. The bath?

When did I get here?

Something soft pressed against my head—squishy, comfy. Moving, I felt something firm—

Whoa!

I bolted upright. Behind me, Miu was under me—naked!?

Wait, it's the bath. Naked's normal… no, that's not it!

Looking around, Rias, Akeno, Asia, and the club members were sprawled on the floor, expressions blissful.

What happened!?

I shook Miu. "H-Hey, Miu? You okay?"

Her body jolted. "Huh?"

"Miu?" I asked again.

Her eyes fluttered open. "Onii-chan… you're back… thank goodness…"

Back? What's she talking about?

I was lost. And, uh, hard to know where to look with everyone naked. Thanks for the view, brain-saved!

No, focus! Wake them up!

I carried each upstairs.

In the Hyoudou family meeting room, the club and Azazel-sensei gathered. I was prostrating before the girls.

They explained everything, and I was floored. I'd turned into a kid, sucked their chests, and reverted? And I did it to everyone?

No memory of it. I didn't know how to apologize.

Azazel sighed. "Restoring you by… that? I ran around all day for nothing."

"Kiba and I scoured the Underworld library," Gasper added.

You too, guys…?

"Sorry," I said. "This is new to me too."

I'd shrunk slightly before from overusing Renkan Keikikou, but never to a toddler with memory loss.

"It's fine," Azazel said. "You're back. My fault too."

The guys were relieved, but the girls—except Xenovia—blushed and avoided my gaze. How much did I mess up?

Rias spoke. "I'm glad you're back, Issei. I told them to offer their chests, but… not that intensely."

That intensely? How far did I go?

"You suggested it!?" I blurted.

"It was… unexpected," Akeno said.

"I got sucked a lot…" Asia mumbled.

"Me too…" Koneko added.

"Three times for me," Miu said.

"No big deal," Xenovia shrugged. "Like childcare practice."

"Not everyone's as bold as you," Reynare said. "I nearly fell…"

"Haha, I was… swept away…" Irina laughed.

Whoa, what did I do!? How much did I crave their chests!?

This is bad. Can apologies fix this?

"Do I… die to atone?" I stammered.

Azazel patted my shoulder. "You know what to do. Take responsibility."

"Responsibility?" I gulped.

"Yeah," he said. "Do that, and they might forgive you."

I looked at the girls. Still blushing, but they met my eyes.

"Uh… if I'm enough…?" I ventured.

Their faces brightened. Guess I'm okay?

"Phew, I'm beat," Azazel said. "I'm out."

"Gasper and I too," Kiba said. "See ya."

"Goodnight," Gasper added.

They left, leaving me with the girls. Awkward silence.

"Uh…" I started, but a magic circle appeared. There was Azazel again.

"Issei, forgot to mention," he said. "Tomorrow at 5 p.m., your tokusatsu show Oppai Dragon premieres. Watch it."

…

The room froze. I'd been told to keep it secret, so they didn't know.

"EHHHHHHHH!?" the girls' shocked voices echoed through the house.

Afterward, they grilled me about the show, temporarily forgetting my chest-sucking fiasco.