Isekai Mizuki S1 - A World With Demons

Chapter 115 - That Cursed Night

Kokushibo was training in his domain, built in Muzan's fortress. He rapidly cut the pillars and tough metal poles that were for his training. His slashes were clean, flawless, and they were accompanied by chaotic little crescent-shaped blades.

After a while, he decided to rest. He sat down, and looked up. "...was this really worth it...?" he asked himself, looking at his palm. "Why... Yoriichi... why...?! Why did you have to outperform me like that...?!" he then questions, putting his hands on his head.

-=FLASHBACK=-

Narrator: Kokushibo

I was a great samurai, just like I dreamed of. I had a kid, and a wife. We were a small group just camping out in the woods. We were all eating, and the fire was dying down. Suddenly, one of my allies stood up, said he's going out to gather some firewood. The others and I wished him luck, and kept telling stories around the dying flame.

A few minutes passed, and the fire was barely standing right now. Another one of us stood up to check what was happening to him, when suddenly, we heard footsteps. We drew our swords, ready for what was coming. Suddenly, the comrade who had gone to grab firewood crashed through. Before we could say anything, he yelled "RUN! NOW!" as he was dragged back into the darkness.

The rest of us heeded his warning and ran for our lives together. We didn't spare a second as we tried to run out of the forest for refuge, when suddenly, the thing that killed our ally took two more of us out, then three more. Only I was still alive anymore. Suddenly, the creature that killed them subdued me. I stabbed its heart, the blade protruding through its back with its heart at the end, but it only regenerated, making my sword stuck.

I thought it was the end, when suddenly, its head was cut off, and it faded into ash. A person landed on the ground, flapped their sword to clean off the blood, then sheathe the blade. They turned around, and suddenly, I felt shock, jealousy and anger at all once. The person who killed that creature was Yoriichi, alive and well, and even stronger than when he was a child.

"I'm sorry for being too late to save your friends, brother," he apologized. He knelt down and prayed, wishing better luck for my friends if they were ever to be reborn. I then asked how he killed it. "That creature that attacked you and your friends... is a demon," he replied, standing up. I asked what a demon is.

"A demon is a human that was transformed by a man named Muzan Kibutsuji. They have regenerative abilities, have great strength, and limitless stamina. Only sunlight and a special kind of sword can kill them. The special sword is made of nichirin, a metal that absorbs sunlight," Yoriichi explained, passing a calabash gourd of water to me. I drank the water while I listened to him talk.

"You have kids of your own, right?" he asked. I looked at him and nodded. "Must be nice," he continued, vanishing from my sight. I wanted to follow his path. I left my family to pursue the path of the Demon Slayer. I joined my brother and the others in cutting down demons, and we would watch as Yoriichi gracefully imbued his sword with flames to kill those creatures.

We asked him how we could have these techniques as well, so he taught us what he created and dubbed "Breathing Magic." However, none of us could ever properly learn, let alone master, his Sun Magic technique. So, he decided to work it around our weaknesses, and create derivatives of the Sun Magic. Flame Magic, Rock Magic, Water Magic, Thunder Magic, and Wind Magic. Those were five of the six derivatives made of the Sun Magic.

Sun Magic (The first ever breathing magic, cultivated by Yoriichi Tsugikuni. After Yoriichi taught it to another person, it was rumored that another person unlocked a new power along with the knowledge of the Sun Magic after mastering it. The Sun Magic would then run down the Kamado family, going through seven more successors. The current holder is Tanjiro Kamado, the ninth user, and both him and the seventh user of the Sun Magic are affiliated with the Slayers Corporation.)