Seirei Tsukai no Blade Dance (Fanfic)

Prologue

A boy wandered in the passages of the Instructional School while carrying an ominously black sword. Though he was a boy, he had beautiful waist-length ebony hair and a girlish appearance. If asked, 10 out of 10 civilians would say he was " a stunningly beautiful girl with uncaring eyes" only the organisation which raised him and some people knows his real identity and all of them are all DEAD.

After all, he was an assassin, and not just an assassin either. He was the best assassin trained in the Instructional School, a secret organisation based in the Ordersia Empire that trains assassins from a very young age. It was an organisation that worships the Demon King Solomon.

Spirit contracts can only be established by pure maidens, but only one man in history changed this fact. It was Solomon, the Demon King. He managed to contract with 72 Demon Spirits and almost destroyed the world from his greediness and will to rule the world. But that failed because the Elemental Lords made an existence of the Sacred Queen, in order to protect the world.

A year after the destruction of the Instructional School, which was Rubia Elstein's doing(Only some knows)
Kamito was taken in by her to help her destroy the Otherworldy Darkness together with some members of the Instructional School who managed to survive on the attack of the strongest fire spirit Laevateinn.

[FLASHBACK]

"BOOM!"
"""What's that noise??""" the instructors shouted together
A student came rushing in to their office
"SIR! An attack from a big giant fire spirit!"
""''WHAT??"""

Almost all members were killed except for Kamito. Well, that's just what he thought.

Suddenly, a shout can be heard from the back.
"Oniiiiiiiii-samaaaaaa!!!" a girl with ash grey hair in twintails and marine-blue eyes came running and hugged him.

"Muir! Your alive??" said Kamito with a very surprised expression.

Muir pouted for a moment and shouted
"Do you think I your little sister The Monster of the Instructional School , Number 2 in ranking would die of mere fire!?"
"Ye-No.. of course not ehehehe.."
sweatdropped for a moment.

"Well that was impressive" a girl with long red hair with ruby eyes jumped of the gigantic fire spirit
"Why didn't I saw you standing there? Did you just arrive?" said Kamito with a rather bemused expression
"Your eyes aren't as sharp as they look it seems, boy" said the redhead in princess maiden outfit.
"Since you survived Laevateinn's attack, You must have some skills.. How about joining me? I'm saving the world."