Reincarnated in DxD With the 100X System

[Ding!]

[100X SYSTEM ACTIVATED!]

The words slam into my brain like a divine decree from the heavens.

I jolt upright, heart pounding. A voice—clear, mechanical, and completely unreal—echoes in my head.

Wait. WAIT. Did I just—?

My vision suddenly floods with golden text, a glowing blue interface appearing in front of me like something straight out of a game.

『100X SYSTEM』

Effect: Everything the user does or gains is multiplied by 100X.

My brain stalls.

Hold up.

🔹 If I do one push-up, it's like doing a hundred?

🔹 If I train for an hour, it's a hundred hours of progress?

🔹 If I gain one stat point, I get a hundred?!

…Holy. Freaking. Hell.

I sit there, frozen, staring at the glowing system screen like it's the greatest gift humanity has ever received.

I—

I actually got a cheat ability.

And not just any ability.

This is broken. Absolutely busted.

A manic grin spreads across my face.

"…Oh. Oh-ho-ho. This is gonna be good."

I throw my head back, laughing.

I came into this world as a fat joke character, but screw that.

With this power, I can grind my way to the top at insane speeds.

My eyes gleam with newfound determination.

Alright. Time to put this 100X System to the test.

I stand in the middle of my ridiculously oversized bedroom, cracking my knuckles.

The system's description still lingers in my mind—everything I do gets multiplied by 100X.

If that's true, then theoretically… I should be able to speedrun my way to peak fitness.

I glance down at my current state—

Pudgy arms. Soft stomach. Zero definition.

I poke my belly.

It jiggles.

Gross.

"Alright," I mumble. "Let's start simple."

I drop into a push-up position—or at least, I try to.

🔹 My arms wobble immediately.

🔹 My gut presses uncomfortably against the floor.

🔹 Everything feels wrong.

"Just ten minutes," I remind myself. "How hard could that be?"

One Push-Up In…

"URGHHH—!!"

My arms tremble like a rickety old bridge in a hurricane.

Before I even get halfway down, my forehead slaps the floor.

I wheeze.

Alright. Let's Try Sit-Ups.

I place my hands behind my head, take a deep breath, and—

…I barely lift my shoulders.

I try again. No movement.

🔹 Come on, body, work with me here!

With a guttural war cry, I force myself halfway up—only for my abs to immediately betray me.

My entire torso flops back down like a deflated balloon.

I lay there, panting, staring at the ceiling.

Sweat pours down my face.

My breath comes in ragged gasps.

I've only been at this for ten minutes—and I already feel like I ran an ultra-marathon.

"God," I groan, limbs sprawled out.

Maybe I'll just take a little break—

[DING!]

『100X System Activated!』 

…Wait.

A sudden heat ignites in my core, spreading outward like an electric surge.

🔹 Pins and needles dance under my skin.

🔹 My muscles tense, my breath sharpens.

🔹 Something inside me shifts.

Then—the real change begins.

My stomach tightens. My arms harden.

A foreign strength floods my body, melting away the sluggish heaviness.

I stagger forward, heart pounding as I watch my reflection morph before my eyes.

This—this isn't normal.

🔹 My bloated stomach? Shrinking.

🔹 My flabby arms? Hardening, bulging with definition.

🔹 My legs? Lean, powerful, athletic.

It's like watching months of intense training happen in real time.

I stumble closer to the mirror, hands trembling.

The pudgy, round face?

Gone.

In its place—

🔹 Sharp jawline.

🔹 High cheekbones.

🔹 Sculpted, chiseled features straight out of an anime protagonist factory.

I cautiously lift my shirt—

🔹 Eight. Pack. Abs.

I gasp.

"Holy crap… did I just speedrun six months of gym in ten minutes?!"

I twist, flexing an arm—biceps, triceps, perfectly toned muscle.

I went from soft and sluggish to peak athleticism in literal seconds.

——————————

A wide, manic grin spreads across my face.

I came into this world as a joke character.

But now?

Now, I look like the main protagonist.

I throw my head back, laughing.

🔹 "Oh-ho-ho! It's over for you now, Issei Hyoudou!" 🔹

I stand in front of the mirror, still flexing, still admiring the absolute masterpiece that is now my body.

Eight-pack abs? Check.

Broad shoulders, chiseled jawline? Check.

Zero trace of my previous "walking punchline" physique? Check.

The transformation is so drastic I half-expect some dramatic anime OST to start playing in the background.

I roll my shoulders, feeling the newfound power coursing through me.

This 100X System isn't just some minor advantage—it's a game-breaking power-up.

If I use it right, I won't just be surviving in this world.

I'll be dominating it.

————————————

Step 1: Survive

This isn't some harmless high school romcom.

This world is a supernatural war zone disguised as an ecchi anime.

🔹 Fallen Angels? Will shank me in a dark alley without hesitation.

🔹 Stray Devils? Literal man-eating monsters.

🔹 The Supernatural Big Leagues? Gods, dragons, and beings that could erase me with a sneeze.

And the worst part?

I wasn't even supposed to be important.

I wasn't reincarnated as Issei, Vali, or some hidden genius.

I was just some rich, spoiled, unimportant extra.

That changes now.

I crack my knuckles.

I refuse to be cannon fodder.

Step 2: Gather Allies

And if they happen to be gorgeous anime waifus?

Well.

I mean, come on—

🔹 Rias Gremory?

🔹 Akeno?

🔹 Koneko, Xenovia, Grayfia…?

This world was practically designed for it.

And unlike a certain dense idiot, I actually understand romance.

With my looks, charisma, and the 100X System, it's only a matter of time before I make waves.

Step 3: Master the 100X System

This power is busted—but only if I use it properly.

🔹 How does it work for skills?

🔹 For magic?

🔹 For supernatural energy like Ki or Demonic Power?

If I play my cards right, I could go from "random side character" to "strongest being in the World."

1️ Grind my stats. Strength, endurance, speed—I need to max those out ASAP.

2️ Learn magic. Even if my physical stats become insanely strong, I won't stand a chance against top-tier enemies without magic and sacred gear-level abilities.

3️ Make connections. This world thrives on factions and power struggles. Strength alone isn't enough—allies are just as crucial.

By the time the real plot kicks off, I won't be some side character sitting in the background.

I take one last look in the mirror, my confident smirk practically radiating main character energy.

"Issei," I chuckle, running a hand through my now-flawless hair. "Enjoy your screen time while it lasts. The real protagonist just logged in."

This world is mine for the taking.