This is an idea that I wanted to do for the ''Non-One For All Izuku'. I want to mash those two worlds together, now this isn't connected to Demons and heroes. This is where Izuku just need practice and work in order to master his breath style and become a great hero. What kind teacher better than all of the Hashiras to help him get all the strength that he needs to become a hero. Now I will put the reason why Ubuyashiki would allow them to teach Izuku and don't worry Nezuko and Tanjiro will appear but later. But for now, let's start this story.
At first the world was a normal place but soon everything changed when a baby in China started to glow.
''Once this anomaly started a new element in the DNA called quirk was confirmed to be on every human being at the time.'' Narrated Izuku Midoriya.
The people soon started to gain all kind of abilities and use them to their everyday occurrence.
''Suddenly dreams and ideas that were thought as impossible become a reality. Thanks to quirks one profession that many people thought to be a myth finally became a reality, people were becoming heroes.'' Narrated Izuku.
''However, with every good user there are the bad users. Villains and other kind of sinister foes that use their quirks for self-benefits and profit. Outside of that there is something far worse than these people, something that was also thought to be a myth but its also a reality. Demons.'' Narrated Izuku.
''These demons are the most powerful and terrifying foes that the heroes never knew about it. Me however discovered that they were real and fought hard to eliminate them thanks to my teachers. I am Izuku Midoriya and this is how I became the number one hero and one of the greatest Demon Slayers of the world.'' Narrated Izuku
I won't tell what breathing Izuku will receive, but it will shock some of you. Also, this will take place in modern times, but the Demon Slayers are like a secret organization. So lets all be prepared for the next chapter.
