My Sacrifice System Summons Unlimited Blades

The world promised me an ordinary life, but then spiritual energy surged, Earth expanded, and anime waifus became demon lords and assassins! Now, I'm stuck in a school where monsters and heroes clash, forced to hide my true power while everyone else struggles to awaken. Luckily, my \"Sacrifice System\" arrived. Throw in anything—a rusty sword, a stolen lunch—and it spits out god-tier abilities. From 'Unlimited Blade Works' to 'Fantasy Collapse,' I'm secretly B-rank, stronger than most teachers, but I registered as a weak 'Archer' to stay low-key. Just as I thought I could quietly build my \"Crystal Palace\" harem, the Crimson-Haired Devil, Rias Gremory, swooped down. She saw through my disguise... and wants me to join her family. Can I maintain my secret while navigating a world where my favorite characters are now dangerous, powerful beings?