Amaterasu

Prologue

Nezuko And Tanjiro were in pursuit of Upper Moon 4 as he ran away like a coward when Nezuko felt agonizing pain on her face. She could feel her flesh burning up with pain like nothing else as her skin curled up and dusted. Her eyes widened at the realization that the sun was coming up and shrunk down to protect herself. Tanjiro turned around in panic shielding his sister from the sun's lethal rays, but worried about the demon eating the villagers. He couldn't lose his little sister, but if he protected Nezuko, the demon would make it to the village before the sun could finish it. Tanjiro was truly at a loss for what to do for the first time in years.

He won't make it in time. Something whispered to her. Nezuko couldn't let that happen, not after everything they'd done up to this point. She couldn't let other villagers die in exchange for her life, especially since she wasn't even human enough to be worthy of sacrifice. There was only one option here for her. 

Using every bit of strength she had left in her burning body, she grabbed Tanjiro's uniform and hurled him toward the demon, ignoring his confused and hurt expression when their eyes met. Instead, she gave him an apologetic smile that even the bamboo couldn't cover. Sorry onii-chan, but it's better this way, right?

She could see the tears even from where she lay dying in the sun, but Tanjiro steeled himself for the final blow and Mezuko couldn't be more proud of him. Through some form of mercy from the gods above, she was able to stick around long enough to see him slay the demon and know her sacrifice was not in vain. 

She could hear her family from the other side (or maybe that was Genya and that hashira?), telling her it wasn't time yet and she still had much to live for, but Nezuko had already accepted her fate, a fate decided the moment she was turned. After more than two years of constant mental battles with the demon within her, she could finally rest in peace. With that in mind, she closed her eyes for the last time, a content smile on her face.

But then she woke up.