Sensei (Kimetsu No Yaiba)

Prologue

In early 800s, there was an unknown darkness began to lurk in the small village at the corner of Japan, and began to consume many weak human. They turned them into a cannibalism that eat their own species.

As it spreads around 3% population of Japan, everyone began to feel restless. However, a swordman resorts to fight the berserk using his sword. No one knows how he did, but it was the first time in history that a human was able to kill a berserk.

Thus, an organization was built, although it wasn't widely known. Many youngsters began to train day and night to perfect their swordmanship, and to gain a renowned titles that every swordmen looked up to centuries later.

"Dad ?" Over the thick snow, Aranea scanned the forest. She was getting worried after not seeing her father that passed the curfew where he supposed to be home before seven in the evening. The forest was already dark, only the source of light of the fire remains.

"Dad ?!" she shouted again, her heart wont stop beating harshly. It was at the moment, she saw a shadow emerge from the dark, and her eyes widened.

"Aranea !" 

She ran towards the older male and wrapped him in a hug, which in turns, he did the same even tighter.

"Dad, I was worried about you."

"You can't be out here ! Let's go home." He scolded and brought her home safely. It was gladly no berserk, or demon lurking anywhere. The new generation called them a demon now after a frightening encounter 25 years ago.

"You shouldn't be out there after the curfew, Aranea !" her father scolded her during their dinner time.

"Dad, there wasn't any demon." she replied back.

"Yet, still dangerous. Never go out there recklessly again." he emphasized, and her face turned guilty. Her mother did not say anything as she did not have any idea how. Their daughter was already 10. She was old enough to learn the good and bad.

Therefore, trying not to embarrass their only angel, the mother knocked on her bedroom door and entered with her permission. Her mother smiled when she saw how she was still guilty of what happened.

"My angel, your father was only worried about you. It was only 30 years when they came to exist, and we still unable to secure the berserk and they were still freely in the dark. Only if we know the weakness other than the ember of the fire." her mother said, caressing her daughter's head on her shoulder. Her heart was heavy, thinking their daughter was unable to experience a childhood like they do.

"We love you so much, my dear. Be strong and live your life."

She didn't say anything, not knowing that would be the last time they would hear and see her parents.

Her body shaken as she looked to where her parents were. They were laying on the floor on top of each other, blood were everywhere around them. Their eyes were still opening in horror, and her father's were staring straight at her.

"Father ! Mother !"

She ran towards her dead parents, where her father's arms wrapped around her mother. Until the end, her father tried to protect her mother.

Aranea gathered them in her small arms, crying alone in the darkness, hoping everything was a nightmare.