Demon Slayer: My Blocks Can Save Everyone

[Everyone is friends, no breaking up canon couples, and all relationships follow the original story. I'm a shameless multishipper, but I'll ship every pairing anyway!] My name is Saotome Ritsuki, and I transmigrated into Demon Slayer. The System said that if I could achieve a happy ending for everyone, I could stay alive in this world. Me: Could someone with a third-grader's taekwondo skills fight an Upper Rank? System: We've got a great starter pack for you! So it gave me a “Minecraft” cheat. I stared at Creative Mode and fell into deep thought... Everyone else uses Nichirin Blades to slay demons. Am I supposed to mine my way through the Infinity Castle with a pickaxe and blow Muzan to smithereens with TNT? And so things started getting weird: When Tanjiro grasped the Hinokami Kagura, I was chomping on an enchanted golden apple to restore my health. I healed the seriously injured squad members with potions, and the Kocho Sisters stared at me. “Are you sure that's just some folk remedy?” I gazed at the Minecraft Creative Mode button and smiled. “Master, back home we call Nichirin Blades ‘Netherite Swords with Sharpness V.’” Keeping everyone alive? Easy! The manga was brutal back then, but now I'm free to do whatever I want! The final battle began. Standing in the Infinity Castle, I smiled at the Minecraft interface. “You pathetic boss, welcome to... my world.” But at some point, it seemed they had taken over my world, too. [Heart-pounding redemption + goofy everyday life + easygoing world-saving + an inspiring tale of using a Minecraft cheat to save everyone whose ending left you heartbroken!]