Reborn as Issei Hyoudou: The Phat to Supremacy

The forest was silent.

The only sound was my slow, measured breathing as I stood in the clearing, my hand still extended where the boulder used to be.

Not shattered. Not broken. Gone.

Hakai wasn't just destruction. It was absolute erasure.

The realization sent a thrill through me.

This power… it wasn't just strong.

It was dangerous.

I clenched my fist, watching the remnants of violet energy flicker out of existence around my fingers. If I had unleashed this in a battle, would I have been able to control it? Or would I have accidentally erased something—or someone—I didn't mean to?

I needed to train.

I needed to master this power.

But before I could think further, a notification appeared in my vision.

[Multiversal Chat Group]

[Supreme Sorcerer]: I sensed that. Newbie, what did you just do?

[Demon Lord in Disguise]: That wasn't normal.

[God of Thunder]: By the Allfather… what kind of power is this?!

[Tactician from Another World]: This is something beyond mortal understanding… fascinating.

[The Caped Baldy]: Oh. That's some serious stuff.

[Perverted Dragon Emperor]: Just… testing something.

I smirked.

I had their attention.

Now, it was time to use it.

[Perverted Dragon Emperor]: Since you're all so curious… got any advice on controlling a power that erases things from existence?

For a second, the chat was silent. Then—

[Supreme Sorcerer]: That depends. Are we talking about magical erasure or something more… fundamental?

[Demon Lord in Disguise]: Judging by the disturbance I felt, this is closer to divine annihilation than simple destruction. It reminds me of something…

[God of Thunder]: Destruction? You wield a power of annihilation?

[Tactician from Another World]: You didn't just destroy something. You erased it from reality. That's an entirely different level.

I let their words sink in.

Even they were thrown off by it.

That meant Hakai was beyond the power scale of most supernatural forces.

And if I played this right… I could get them to help me master it.

[Perverted Dragon Emperor]: Yeah, it's pretty insane. I need control, though. Any ideas?

A moment passed before a new message popped up.

[Supreme Sorcerer]: I can send you techniques on energy manipulation. Learning to condense and direct the flow will keep it from going out of control.

[Demon Lord in Disguise]: I have experience with destruction magic, though your power seems… different. Still, I can give you some pointers.

[God of Thunder]: A warrior must master his weapon! I shall teach you the discipline of control!

[Tactician from Another World]: I'll analyze your energy pattern and suggest efficiency tactics.

[The Caped Baldy]: Eh. Just hit something until you get used to it.

I snorted. Of course, he would say that.

But this was perfect.

I wasn't just figuring this out alone—I had mentors from different worlds.

[Perverted Dragon Emperor]: Alright. I'm ready to learn.

[Training Begins]

For the next few days, I pushed myself to the limit.

Following the advice from the Chat Group, I started with basic energy control.

• Supreme Sorcerer's lessons helped me shape and manipulate the Hakai aura, condensing it so it wouldn't leak out uncontrollably.

• Demon Lord's teachings showed me how to direct focused destruction rather than just unleashing raw annihilation.

• God of Thunder's discipline drilled me in precision, timing, and stamina.

• Tactician's calculations helped me optimize the energy output to reduce unnecessary waste.

And then… there was The Caped Baldy's method.

Which, to be fair, was just "punch stuff until you understand it."

But surprisingly… it worked.

The more I practiced, the more natural Hakai became. I could summon it in an instant, control the size and intensity, and—most importantly—I could contain it.

At first, even just forming a small sphere of Hakai was difficult.

But after a week?

I could erase a target the size of a tree with nothing more than a flick of my wrist.

And the best part?

I hadn't even gone all out yet.

[First Real Battle: The Stray Devil]

One night, Rias called me to the clubroom with a serious expression.

"We have our first real mission," she said.

I already knew what this was.

The Stray Devil Hunt.

In the original story, this was Issei's first battle. A test. A lesson.

Except this time?

I wasn't the same Issei.

We arrived at an abandoned church, the air thick with a sinister presence. Inside, the Stray Devil lurked—a grotesque abomination with too many limbs, twisted features, and an aura of bloodlust.

"You devils… always ruining my fun," it snarled.

Rias stepped forward. "You betrayed your master. You know what happens now."

The Stray growled, its form shifting unnaturally.

In the original story, this fight was a struggle for Issei. He barely managed to hold his own, relying on Boosted Gear and Kiba's support.

But this time?

This was my chance.

I stepped forward, cracking my neck. "Let me handle this."

Rias blinked. "Are you sure?"

I grinned. "Yeah. I want to test something."

The Stray lunged, moving faster than a human could react. Claws slashed toward my chest—

I didn't move.

I didn't dodge.

I raised my hand and simply whispered—

"Hakai."

The moment my aura flared—

The Stray froze.

For a split second, it realized something was wrong.

Then—

It vanished.

No screams. No blood. No remains.

One second, it was there.

The next?

Gone.

The room was silent.

The entire Occult Research Club stared at me, eyes wide.

Kiba's polite mask cracked, his expression shifting to shock.

Akeno's usual teasing smile was nowhere to be seen.

Koneko actually dropped her snack.

And Rias?

She just stood there, mouth slightly open, as if she couldn't process what she just saw.

"…What was that?" she finally asked, her voice quiet.

I let my hand fall to my side, the last wisps of Hakai energy fading.

I shrugged. "A little something I picked up."

Silence.

Then—

Akeno laughed, a mix of delight and disbelief.

"My, my~ Now that was unexpected."

Kiba chuckled, shaking his head. "You… are something else, Issei."

Koneko just stared. "…Scary."

But Rias…

Rias was still looking at me.

And for the first time, I saw something new in her gaze.

Not confusion.

Not shock.

But curiosity.

Like she was reevaluating me completely.

I smirked.

Yeah.

This was just the beginning.