Immortality Forces Me to Slay Demons, and I Become Unrivaled

“Heh heh heh! Demon, don't run! Your lifespan and I are destined to be together!” He can use his lifespan to refine martial arts techniques. As long as he has enough years to spare, he can become a saint on the spot. This world is overrun by demons. Some wear human skin and serve as high-ranking officials in the imperial court, secretly devouring countless people. Some great demons can swallow an entire city of humans with a single gulp. Lin Yuan transmigrates into this world. As an ordinary man, he has a lifespan of less than a hundred years. He's just a lowly constable in the Demon-Slaying Bureau, with no illustrious family background or inherited martial arts. Fortunately, he awakens the Lifespan-for-Power System. Killing demons earns him their remaining years, which he can use to refine martial arts techniques. From [Village Wolf Demon] to [Dragon King of the Great River] From [Savage Bull Body Tempering Art] to [Indestructible Golden Body] Lin Yuan looks at the densely packed lifespan figures on his status panel. He grins. I refuse to believe that with all these countless years to pour into it, I can't forge a path straight to the heavens.