Title: I Became Invincible in Demon Slayer
This is the story of young Seiji Takeshi's journey after transmigrating.
Having transmigrated to the world of "Demon Slayer" with his own demon-slaying system, Seiji Takeshi says, "No worries, I've got this!"
"I'm Seiji Takeshi, but I'm going with the local custom and calling myself "Nagasawa Aoyama" now. That's because when I transmigrated, I accidentally broke an old man's roof, and now I'm stuck here doing hard labor..."
"Well, it's not exactly hard labor. I don't actually do any work. The old man just makes me run back and forth on a mountain that has thin air and traps. The old man calls everything I'm doing training, but he can call it whatever he wants. I just want to rest for a bit."
"Oh, I almost forgot to mention, the old man is a trainer. His name is Urokodaki Sakonji..."
"...After being here for a few days, I've realized that this isn't an ordinary world..."
"This is the world of the super popular anime – Demon Slayer!!!"
"The story is set in the Taisho period in Japan."
Chapter 1: Transmigrated with My Own System!
"After the sun goes down, demons come out and eat people. But there are also demon slayers who kill demons and protect people."
"When Takeshi came to this world, he brought his own demon-slaying system. The system comes with a Light Breathing Technique."
"Right now, Mr. Urokodaki doesn't know about this. He's determined to teach me the Water Breathing technique and train me to be a demon slayer. But I have my own demon-slaying system, so whether he trains me or not, I'm going to be slaying demons anyway."
"Still, having two breathing techniques can't hurt."
"The last rays of sunlight are gradually disappearing, and night has fallen."
"Takeshi opens his eyes, looking at the pitch-black surroundings. He didn't realize he'd actually fallen asleep. Oh well, I need to get up and go back to eat!"
Whoosh!
"He hears a strange noise coming from the grass nearby."
"Takeshi immediately becomes alert. He holds his wooden sword and stands still, staring at the grass where the noise came from."
"Suddenly, a dark figure jumps out of the grass. He looks closely and sees that it's just a rabbit. Takeshi sighs in relief, then thinks, 'Braised rabbit must taste great!'"
"He jumps up, easily leaping into the air. But then, he feels something wrap around his ankle."
"He looks down and sees a long, wet tongue wrapped around his ankle."
"Hahaha, I caught another one! Hahaha..."
"A long-tongued demon lying on the ground is laughing in a creepy way. His tongue is pulling hard on Takeshi's leg. If he eats just one more person, he'll become stronger, and even the lowest-ranked demon slayers won't be able to defeat him."
"Takeshi is disgusted. He spins in the air and swings his wooden sword, whoosh, cutting off the tongue attached to his ankle."
"He lands steadily on the ground. Demon blood is dripping from the wooden sword."
"Having been here for a few days, and knowing that there are demons, I didn't expect to see one here, and... it looks so disgusting."
"Now's not the time to complain. Takeshi's face becomes serious. To deal with demons, you need a Nichirin blade or sunlight. It's dark right now, so there's no sun."
"He hasn't participated in the Final Selection yet, so he doesn't have his own Nichirin blade. The only thing he has is the old man's wooden sword."
"Gahahaha... kid, with just a wooden sword, you're not afraid, and you're not running away? Are you underestimating me?"
"At the same time that the long-tongued demon finishes speaking, the tongue that he just had cut off instantly grows back, and it's even longer and thicker than before."
"Looking at the long-tongued demon, Takeshi gives a faint hum, and says, 'Oh, I am underestimating you.' His hand grips the wooden sword, Total Concentration Breathing."
"The blood in his body is rapidly heating up, and the speed at which it flows is also accelerating."
"Total Concentration! Light Breathing! First Form: Flash!"
Whoosh, whoosh!
"Takeshi moves incredibly fast. By the time the long-tongued demon can react, he's already standing behind the demon. The blood flowing on the wooden sword is even more than before."
"An 'S' shaped wound appears on the long-tongued demon's body, stretching from his face all the way down to his leg. Fresh blood spurts out from the wound."
"Gah, you brat, have you forgotten what I just said? A wooden sword can't hurt me. I can immediately regen..." He didn't even have time to say the word "regenerate."
"The wound on the long-tongued demon starts to heat up, and then a light bursts out. The long-tongued demon's body expands outwards from the wound, bit by bit disappearing into ashes."
"This, how, a wooden sword... how is this possible..."
"The long-tongued demon dies with his eyes wide open. The brat he mocked killed him with a wooden sword."
"The "Light Breathing" has the attributes of "Sunlight". Even without a Nichirin blade, it can still effectively slay demons."
"Ding! The host has slain a common demon. The system rewards you with +5 to your body's strength, and randomly gifts you a bottle of explosive body enhancement potion!"
"The system's notification clearly appears in his mind. Takeshi feels that his body has indeed undergone slight changes, so it should already have been strengthened.
The bottle of body enhancement potion has been placed in the system's inventory, and he can take it out whenever he needs it."
"What Takeshi finds a bit regrettable is that the rabbit from just now has already run away. His braised rabbit dish is off the menu."
"Wiping the blood off the wooden sword, Takeshi slowly and leisurely walks down the mountain.
Mr. Urokodaki should be waiting for him to have dinner. He's also feeling hungry, so he hopes that tonight they'll have some meat, to replenish his strength."
"Footsteps finally sound outside. Under Urokodaki's tengu mask is a gloomy face. He had already told Takeshi that when the sun sets, he absolutely must return quickly."
"On Mount Sagiri, it's only relatively safe, it's not absolutely safe."
"I'm back! Mmm, smells really good, are we stewing meat tonight?" Takeshi puts down the wooden sword, sits down, and waits for dinner to be served."
"When it gets dark, you need to..."
"...Come back quickly! I know, I know, let's eat!"
"The words he wanted to say are interrupted by Takeshi. Urokodaki doesn't say anything more. Let's eat dinner!"
"The reason why he decided to train Takeshi is that he saw that he has the potential to become a demon slayer.
It's just that this person of his sometimes seems a bit unreliable. He doesn't know if he can really be competent in this profession."
"This is what Urokodaki is somewhat worried about."