Demon Slayer X Male Half Demon Reader

Centuries ago, before even Muzan Kibutsuji was turned into a demon by his doctor due a an incurable illness, Y/n was a seventeen year old demon slayer and member of the strongest clan in his era, the Aren clan. The Aren clan was famous for building generations of tremendously powerful demon slayers, and was feared amongst all the demons in his era, due to their godlike universal breathing technique that was said to have been taught to them by god himself, to protect humanity from the demons. At the time, the universal breathing technique was the primordial figure of all breathing techniques, until the tragic eradication of Y/n's entire clan and all records of its existence was wiped out by the most powerful demons over the globe on a dark and stormy night. The Aren clan's universal breathing technique became lost and the sun breathing technique was born, now known as the most powerful breathing technique in history, as others began to branch from it like the water breathing technique, thunder breathing technique and others. During the eradication of his bloodline, Y/n was spared by the demons and was turned into a half human half demon hybrid, the demons thought that his humiliation would've been worst than death, as he would now become the very thing he despises most... a demon. After a few centuries of slaying demons none stop, Y/n wiped out half of the demons in the world, causing a new demon progenitor to rise up... Muzan. After centuries of countless demon hunting, Y/n lost his memories then fell into a hundred year slumber, and was found unconscious by Gyomei Himejima, while he was training in a forest. Gyomei then brought the sleeping who seemed like he couldn't be awoken, back with him to his master for guidance on what to do with the seventeen year old looking boy. What will happen once Y/n wakes up, having no recollection of his memories and having been awoken in a modernised era that has a new demon progenitor?