A New Life, A New System

Kazuma Shirayuki woke up with a sharp inhale, his lungs sucking in air like a drowning man breaking the surface. His body felt strange—too heavy yet unfamiliar, like slipping into a suit that wasn't his own. His heart pounded in his chest, and a dull ache throbbed in his skull, sending waves of disorientation through his senses.

Where the hell am I?

His last memory was clear—too clear. He had been walking past a gas station, earbuds in, lost in thought about what to grab for dinner. Then—boom. An explosion. A flash of heat. His skin burning. Then nothing.

He should be dead.

The realization sent an icy chill down his spine. He forced himself upright, his hands gripping the edge of the bed he had been lying on. It was soft. Too soft. His fingers sank into expensive fabric, nothing like the stiff mattress he had at home.

Wait… this isn't my room.

He looked around. The walls were dark wood, polished to perfection. A large window let in the warm glow of the morning sun, casting long streaks of light across the floor. A desk sat in the corner, neatly arranged with books and what looked like old-style pens and parchment.

This wasn't right.

His pulse quickened as he stumbled toward a full-length mirror standing in the corner. The reflection that stared back at him nearly made his heart stop.

The man in the mirror wasn't him.

Kazuma had been average. Plain brown hair, unremarkable features, and a body that leaned more toward 'lazy gamer' than 'athletic.' But this guy…

His hair was a striking shade of blue, deep and rich, almost metallic under the light. His eyes were pitch black, sharp and intense. His jawline was more defined, his shoulders broader, and his body…

Kazuma slowly raised a hand, pressing it against his chest. Muscles. Firm. Strong. He wasn't bulky, but his physique screamed power—an athlete's build, one honed through discipline and combat.

What the hell…?

Then, as if the world had decided things weren't weird enough, a translucent blue screen appeared before his eyes.

[Ding! System binding with the host…]

[Ding! Binding successful.]

[System Creator System has been linked.]

Kazuma blinked.

A system?

As in, an actual system? Like the ones in all those power fantasy novels?

His mind raced, but before he could fully process the information, another message popped up.

[Ding! The host can create his first system for free.]

[Afterward, new systems will require PCS (System Creator Points).]

Kazuma exhaled slowly, rubbing his temples. Okay. So, let's recap: he died, woke up in a completely new body, and now he had a system that allowed him to make systems? That was insane.

But a small, twisted grin tugged at his lips.

Insane, but useful.

Focusing on the blue screen in front of him, Kazuma willed it to show more information. Another panel appeared instantly.

[Status]

• Race: Human

• Systems: (None)

• PCS: 0 (First system creation is free.)

There wasn't much, but the fact that he could make his own system meant his potential was limitless. He could shape his own growth, tailor his abilities however he saw fit.

But first, he needed information.

He took a deep breath, sifting through the memories in his head. They were fragmented, as if they had been roughly downloaded into his brain. But soon, the pieces started to come together.

His name was Kazuma Shirayuki. He was a high school student at Kuoh Academy.

Kuoh Academy…

His fingers twitched. That name. It was familiar. Too familiar. He dug deeper into his memories, his pulse hammering against his ribs as realization set in.

No way.

This wasn't just any world.

This was the world of High School DxD.

Kazuma's breath hitched. Devils, angels, fallen angels, dragons, gods—this world was filled with supernatural chaos. And if he was here, that meant he was about to be thrown right into the middle of it.

His stomach twisted. Shit.

He knew how things played out in the original story. The supernatural world wasn't kind to weaklings. If he didn't get stronger, he'd be nothing more than a background character—if he even survived at all.

His eyes flickered to the blue screen floating before him.

Good thing he had a system.

Kazuma cracked his knuckles, a smirk playing on his lips. "Alright. Let's see what this thing can do."

A new prompt appeared.

[Ding! Please design your first system.]

His mind raced with possibilities. Should he go for a combat-based system? A skill-enhancing one? Something that granted him an overpowered ability right away?

No. He needed something versatile. Something that would let him adapt to any situation.

He took a deep breath.

[Creating System…]

[Name your system.]

Kazuma thought for a moment before typing in the simplest, most direct name he could think of.

[Adaptive Growth System]

[Confirm? Yes / No]

He selected Yes.

[Ding! Analyzing system concept…]

[Assigning base functions…]

[Finalizing creation…]

[System Created!]

A new screen popped up, displaying the details.

[Adaptive Growth System]

• Grants experience and skill points from various activities.

• Learns and improves skills at an accelerated rate.

• Enhances combat efficiency over time.

• Provides analysis of enemies and their weaknesses.

• Unlocks additional functions with progression.

Kazuma let out a low whistle.

Now this… this was good.

With this, he could improve at a ridiculous pace. He wouldn't be limited to one fighting style or ability—he could adapt, evolve, and keep growing stronger no matter what.

And the best part? He wasn't at the mercy of a pre-designed system. He made his own rules.

He clenched his fist, excitement buzzing in his veins. This world belonged to the strong, and with this power, he was going to make damn sure he wasn't just another footnote in someone else's story.

This time, he was going to control his own fate.

And if anyone stood in his way?

Well.

He smirked.

They were in for a rude awakening.