Legacy of the Unknown Brave

Prologue

Warning: contains major spoilers for Brave Exkaiser's ending!

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Thousands of years ago,

There was a long-forgotten planet, galaxies away from our Earth. In a glance, it might remind you of this blue planet we're living on, with similar terrains, living beings, and the civilization on it.

Until the Geisters brought chaos onto it, that is.

Dino Geist, the cruel leader of the Geisters, managed to take over an important device that controls the turmoil of the planet's core.

It only took several earth hours for the planet to be turned into a living hell. Cracks appeared on the ground below, fire creeping out of them. People either die either because it was too hot or due to being burnt alive.

A young boy dragged his feet through the rubbles of the destroyed city. Half of his body is practically wrecked, with one of his hands gone and blood covering his sight.
He was the sole survivor of the tragedy, being lucky for spending his time in a fortunately safe area when it happened.

There was nothing but rubbles and fire in sight, other than dead bodies that were slowly getting burnt to ashes. The boy wanted to puke so bad, but nothing came out. With ragged breath, he kept searching for help, and hopefully, another survivor.

The extreme blood loss didn't make it any easier for him. The further he walked, the dizzier he got. His right arm, or at least whatever was left of it, was slowly getting numb, while intense pain covers the rest of his body. Both of his feet finally gave up, causing him to collapse onto the burning ground.

He hissed due to the painful contact with his skin, and his throat released small, weak screams, having the heat crawling over his frail body.

He slowly lost the strength needed to keep his eyes open.

Before he passed out, he saw a trail of light in the sky.
The blue color stood out with the vermilion surroundings.
It was a blue sphere of light.
All of the sudden, it dashed closer to him.

The boy tried reaching out to the sphere, but he was too exhausted and weak, he only managed to move one inch of his finger.
And he lost his consciousness.

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Much later on, at the Space Police headquarters.

A bald alien waved at the redhead. "Oi, Rekka! Aren't you going to see Exkaiser when he arrives?"

"I'll be there in a few minutes, sir! There's something I need to deliver first."

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Rekka was practically sprinting in the hallway.
He hadn't seen Exkaiser in years, and the other Kaisers since they were sent to assist their leader. He missed his caretaker so much, and he couldn't wait to tell him about the trainings he had been going under.

Him and Fighbird have been in high spirits since the news arrived to the HQ this morning:

The Kaisers have successfully taken care of the Geisters.

It was mentioned that four of the underlings have been arrested, while the leader, Dino Geist, committed suicide by burning his body into the sun.

Rekka remembered Fighbird cheering excitedly once one of their instructors told them about it. It was understandable, since Fighbird was a huge fan of Exkaiser.

They did have to deal with the other instructor being pissed at them for being loud, though.

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"Young man, you're going to drop my precious parcel if you continue being hyperactive like that," a mature woman with short light purple hair chuckled.

Rekka stuttered while closing the door behind him, "I-I apologize, Luna, Ma'am!"

Luna laughed at his response. "I was only teasing you, don't worry about it."

The redhead sighed in relief before putting down the box on the nearby desk. "It's surprisingly light for its huge size. I wonder what's in it?"

"An important device for my research. You'll find out sooner or later, don't worry about it."

Rekka hums in curiosity. Luna's research team had always managed to awe him with their unique inventions. He looked up to her for that. He also thought of her as his older sister due to their similar human-like physical features, and he was like a younger brother to the woman.

"Anyways," said Luna while closing her report file, "let's go to the hangar, shall we? I know you'd want to be there once the Kaisers arrive."

The young man's eyes lit up in excitement before realizing something. "Aren't you supposed to give the report to Yuusha Seijin first?"

Luna waved her work tablet and smirked. "Don't worry, I've let him know that I'll be taking a short detour."

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Six glowing spheres appeared in sight, approaching the base with a speed faster than light. They are the Kaisers' energy form.

After confirming their status, the operator team pulled several huge vessels out of the hangar's walls. The vessels opened up automatically, uncovering the Kaiser's space frames.

Their space forms were similar to their Earth ones, without tires nor anything of Earth origins, in the exchange of several pointier details.

"Systems, all green. Kaisers, you're allowed to fuse."

The spheres merged with each of their respective bodies. A few seconds of silence, and their optics flickered online.

The one standing in the first container took a step forward before saluting. "Thank you for your assistance."

"Exkaiser!" Rekka jumped from the hangar's balcony excitedly.

In one swift motion, the previous mech caught him into his palm and smiled softly.

"Long time no see, Rekka."

Notes:
Hi there! Res here ✧◝(⁰▿⁰)◜✧

Thank you so much for reading this story!
I apologize if this fic is messy www, I hadn't written anything properly for like.. five years? I'm open for any criticism and suggestions to improve my writings!

Rekka is my Yuusha OC I have been developing for the past three years while trying to connect most of the Brave Series (I won't include GGG, Might Gaine, and Betterman due to timeline problems). This series is my headcanons and has no relations to the canon!