Began With A Bang, I Relied On Killing Monsters To Lengthen My Life

Only the chosen dead person can reach this place, where killing monsters can exchange for longevity, thus extending life! Qianye, after surviving a near-death battle, finally returns to the mortal realm, only to discover that the longevity' reward comes with a time limit! Once the time limit expires, Qianye once again descends into that desolate and terrifying place! What exactly are these monsters? Is the sudden outbreak of eternal slumber in the mortal world related to this place? Besides myself, who else has been chosen? There's no time to think, death would come quietly!