The One We Couldn't Save

.+* Prologue *+.

PoV: Zenitsu

"The master will see you now." Came the voice of a small, white-haired child. The three Hashiras nodded, stepping inside and kneeling down, "Greetings young Master, how are you feeling today?" Asked the blonde, bowing slightly. "I'm feeling very well today, thank you Zenitsu, please take a seat, all of you."

"I'm sure you three are wondering why I've summoned you today?" The three nodded, kneeling down on the wooden floor, "Due to the sudden passing of Water Hashira, Tomioka Giyuu, we may have discovered something that could help us with finding his whereabouts."

The Hashiras straightened in their seats, practically towering over their young master, trying to get a better listen. "When clearing out the Water Estate of Tomioka's belongings, we found a journal from a few years ago, possibly from when Tomioka was around 19 years old."

"I'd like to task you three, Zenitsu, Senjuro, and Tsuki, all to travel to Mt.Kumotori. This will be a difficult, and possibly life threatening mission, do you accept it?" The three Hashiras exchanged glances, nodded at each other, and then Zenitsu spoke. "Yes Master, we accept this mission." The Hashiras stood up, and bowed before leaving, "Please come back alive..." Only Zenitsu was fortunate enough to hear the whisper.

After a good few days of walking, the group had managed to reach Okutama, a small town near the base of Mt.Kumotori. Zenitsu looked up at the quickly darkening sky, and suppressed a cold shiver. The winter was coming, so nights would last for longer.

The group walked over to the base of the mountain, when the voice of an old man stopped them, "Why are you three out so late? And especially going up the mountain, there's demons up there, don't you know?" The Hashiras turned to face the man before speaking, this time Tsuki spoke.

"Yes sir, we are aware. Thank you for your concern, however we are with the corps, and are on a mission." The old man paused for a moment, before speaking again, "Ah, the corps! Come in, please, you must be exhausted from your travels! Besides, any mission will be safer during the morning."

The three exchanged glances, before Zenitsu stepped forward, "Thank you sir, we will stay for one night, and no more. We do not wish to burden you." The man smiled, quickly opening his door and letting the slayers inside.

When everyone was seated, the old man lit a fire, and began boiling some sort of stew. "My name is Saburo, if I may, what are your names?" He smiled brightly, his already wrinkly face doubling in wrinkles. "Agatsuma Zenitsu, Breath of Thunder Hashira." Zenitsu replied, nodding his head in respect.

"Rengoku Senjuro, Breath of Flame Hashira." Replied Senjuro, a nervous smile creeping up his face, "Tsuki Shio, Breath of Wind Hashira." Came Tsuki's voice last, a warm, pleasant smile greatly contrasting Zenitsu's constant deadpan expression.

"Oh my..." breathed Saburo, "The Hashiras! In my house!" He exclaimed, clapping his hands together. Senjuro gave the man a small smile, before thanking him.

Once the meal was ready, the four sat down to eat, with the occasional conversation between bites. After all four had finished, Zenitsu spoke up "Thank you for the meal sir, however are you sure we are not burdening you?"

"Burdening me? Nonsense! I'll help the corps any day!" Saburo said with a bright smile, "I'm quite lonely you know, so some company is nice."

Tsuki grinned widely, and thanked the man. Saburo stood up, "Please wait for a few moments." He said, walking to another room of his small house. After a few minutes had passed, he came back into view.

"Please follow me," he beckoned to the Hashiras, exting back into the room, all following close behind. Inside the room were three futons layed out for them, "Thank you, kind sir." Said Senjuro, another smile creeping up his face.

As the sun had just begun rising, the three Hashiras left, giving their thanks to Saburo for his kindness, and beginning their long trek up the mountain. After a while, Zenitsu noticed a smaller set of footprints near the path, blood dripped everywhere. How odd...

He paused, placing his arms out to stop the others, shushing them, and listening closely. "Into the trees!" He hissed at them, all three leaping into different trees.

Two hooded figures walked out of the dark forest, the taller gently gripping onto the shooter's arm. The shorter raised their hand, a quiet, gentle, young male voice could be heard, and three demons appeared in a shaded spot.

The demons bowed, before standing up, and began speaking with the shorter hooded figure. They were talking in such hushed whispers, that not even Zenitsu could hear the conversation.

The three demons nodded, disappearing, and the taller one giggled, disappearing in a spurt of pink flames. Zenitsu narrowed his eyes, but shook his head, he wasn't going to think about that right now.

The demon paused, moving its head in a sort of sniffing motion, before looking up at the trees. It made eye contact with Zenitsu and grinned.

Crimson eyes looked up at him, cat-like slits for pupils. He knew those eyes, he knew them more than he knew himself. Those once kind and loving eyes now belonging to a monster...

Zenitsu felt his head spinning, and was sure he was going to collapse as the corners of his vision blurred and went dark. That wasn't just any demon, that was him.

It was The Demon King himself.