Seirei Tsukai no Blade Dance

Volume 4, Prologue

Passages excavated in the solid bedrock were piled up in several layers.

A boy had been walking alone through the inside of the institution where crimson flames swirled.

He had glossy black hair. His attire covered his whole body in black and could be mistaken for darkness.

His girlish looks still retained some innocence, but his jet-black pupils were emotionless, only reflecting the flames that flickered inhumanly.

Who was it that destroyed the institution of the Instructional School, that had many combatants, in merely half a day?— The boy had no way of knowing.

Was it the capital's Spirit Knights, or an accident due to a rampaging sealed spirit?

The instructional teachers, who drilled combat skills into the boy, were nowhere to be found.

Had they escaped, or it might be that they were already dead.

If that was the case, the boy would be released and would become a free man.

But.

(Such things are trivial...)

The boy, who had his heart stolen away, had become apathetic to everything.

Except for her, the one and only exception.

The darkness spirit, Restia— the highest level sealed spirit that was given to him by the teachers of the institution.

The girl had granted light to his heart that was shut in darkness.

(She's the only one that I'll absolutely protect.)

Within the blazing flames, the boy's goal was the shrine that was beneath the institution.

In the shrine, there were many artifacts of sealed spirits that were illegally excavated by the Instructional School —that was strong enough to even be comparable to a small nation's military strength— resting.

The ring that sealed Restia should also be stored over there.

The spirit seal that was the proof of a spirit contract had not yet been engraved on the boy's hand.

The teachers of the institution were cautious of him possessing more power than necessary and had not permitted the exchanging of a spirit contract.

The boy held the power to commune with spirits while having the body of a man— the same nature as the Demon King.

The teachers were afraid that he would rebel after contracting with the highest level darkness spirit.

"—Onii-sama!"

The sound of a girl came from behind.

"Muir?"

There was only one person who would call him onii-sama.

The boy turned around and saw a young girl behind him.

She had ash-grey hair that was tied up on both sides of her head.

Along with her blue clear pupils, she had lovely rose-bud-like lips.

Her skin that could be seen from the gaps of her black combat uniform was white like virgin snow.

"Muir, you still haven't escaped?"

"Mou, I was searching for you, onii-sama!"

The girl —Muir Alenstarl— pouted her cheeks like she was angry.

Naturally, the boy, who was an orphan, had no sisters.

'Onii-sama' was just something she called him willfully.

"What happened to those watching over us?"

"I killed them."

She answered without a flicker of her eyebrow.

"It's because they tried to hinder me from searching for onii-sama."

She neither boasted nor felt regret about the murder.

She just killed because it was a necessary task— It could be said to be something like that.

"I see..."

Although there was no sympathy for those who were killed.

As the ones who had raised her as a slaughtering weapon were none other than they themselves.

Muir Alenstarl was the Instructional School's second ranking combatant.

In this institution literally composed of monsters, the girl was nicknamed “Monster.”

While the boy held overwhelming combat skills, he had not yet killed even a single person. He was a being that drew the line.

"Onii-sama, you too, what are you doing here?"

This time, Muir was the one who asked.

"The ring that sealed Restia is in the underground shrine. I'm going to retrieve it."

"Ah, Onii-sama, as you already have Muir, you don't need things like contracted spirits."

Muir frowned with her cute lips, seemingly bored.

"That reminds me, where's Lily?"

Lily Flame was the seventh member attached to same unit as the boy and Muir.

"Lily?...Uhmm, she might have been killed by the crimson giant."

"Crimson giant?"

"The thing that attacked the institution a few hours ago. That outrageously strong flame spirit."

At that instant.

The ground suddenly shook.

"—It's coming onii-sama!"

".....!?"

Suddenly, from the depths of the passage, he felt an intense presence.

Crimson flames, spouting out high, burned up the ceiling like it was nothing, and at that moment.

What appeared from within the flames was— a roaring giant of flames.

In its hand that was like a lump of lava, it was gripping a sword of blazing scarlet flames.

(A flame spirit? No, that's...)

It was not a simple flame spirit.

A hair-raising chill ran all over the boy's body.

That was the very symbol of destruction.

Just by looking straight at its existence, his mind began being scraped away.

(I'm certain— That's an archdemon class spirit!)

It was the being that had destroyed the Instructional School, that held many elementalists, in merely a few hours.

It was said that the power of a archdemon-class spirit pulled through even a division of the spirit knights.

(This isn't an opponent I can fight without a contracted spirit...)

The flame spirit seemed to have noticed them.

Clad completely in flames, it melted the bedrock as it slowly approached them.

"Onii-sama, leave that to Muir."

Muir licked the ring placed on her small hand.

She planned on using an anti-spirit militarized spirit

"Muir, that is not a being that a human can manage."

"No problem. Muir isn't a human— Muir is a 'monster'."

An ominous spirit seal glowed on Muir's right hand.

No, that was not a spirit seal, but a Cursed Armament Seal that the Instruction School had given.

Jester's Vise — It was the reason why Muir was called Monster.

"Goodbye, Onii-sama."

"—Muir!!!"

The young boy stretched his hands out towards her shoulders and at that moment.

The crimson flames released by the giant thoroughly burned the boy's field of vision.

The "rampaging incident" of the spirit led to the destruction of the Instructional School

That was something from a year before the boy appeared at the front stage as the strongest blade dancer.

It was an event that occurred in a remote region of the empire that was not even marked on the map.