Reborn, I'm crazy in the end of the world

Story of: Reborn, I'm crazy in the end of the world[Rebirth + Multiple Heroines + Group Battle + Extreme Cold Doomsday + Zombie Survival + Brainless Fun + Decisive Killing + Not a Saint + Technological Explosion] Extreme cold is coming, zombies are rampant, why don’t we awaken our superpowers? The protagonist fought to the last moment to protect his love, but was saved by a system incarnated as an elf. After being reborn, he decided to build his own forces and be with his beloved. This book does not have superpowers, and the combat power will not collapse in the later stage. I hope you like it.