My Lifespan Stacks Without Limit, Starting with Slaying Demons

In a world overrun by demons, Lin Fan discovers he can reap their lifespans. Lifespan is cultivation. Lifespan is technique! [Spend fifty years: Evil-Breaking Staff Art perfected!] [Spend three hundred years: Nine Heavens True Thunder Art mastered!] While so-called geniuses are still fretting over bottlenecks, Lin Fan has already carved out an unrivaled path by slaying demons. Then one day, a high-ranking official from the Demon Suppression Bureau personally invites him on a top-secret mission. Their target: a thousand-year-old demon king... “Hmm, how many years of lifespan would that be worth?”