After Seventy Years as a Sect Janitor, I’m Invincible Under Heaven

Qin Chen transmigrates into a lowly servant tasked with sweeping at the Taiyi Sacred Land. At sixteen, he awakens a System that grants him different rewards whenever he signs in at different places. Sign in at the Land of the Emperor's Legacy, and receive the world's greatest Chaos Sacred Physique and the Chaos Emperor Scripture! Sign in at the Sealed Demon Grounds, and receive a quasi-emperor weapon! Sign in at the Artifact Refining Hall, and receive divine-grade artifact-refining skills! Sign in at the herb garden, and receive an immortal elixir! Sign in at the Emperor's Hall, and receive the emperor-grade forbidden divine art, “Immortal Resurrection Art”! Qin Chen thinks he'll just quietly keep signing in until he becomes invincible. Then one day, an emperor's ruins appear within the sacred land, drawing sacred lands, aristocratic clans, and ancient imperial dynasties from all over. A peerless demon king emerges from the ruins, killing countless powerful figures and ruling the world as he threatens to destroy the sacred land. With no other choice, Qin Chen steps out and slaps the demon king to death. He sighs, “I only wanted to be a humble servant who sweeps the floors and quietly signs in. Why did you have to force me to act?”