Xuanhuan: I Become an Old Man from the Start, and Others Cultivate for Me

[Starts out far from invincible + no female lead + old-man protagonist (doesn't grow younger) + satisfying power fantasy + sect-building + not mindless + lighthearted] Rich second-generation Song Rui transmigrates... He transmigrates into a fantasy cultivation world, taking over the body of an old man with no hope of reaching Foundation Establishment, a lecherous disposition, and severely declining physical functions. Just as he feels that his transmigration is like going from a “royal garden” to a “dung pit,” the “Double-Speed Returns for Carefree Cultivation” System suddenly appears and binds itself to him. The System has one main principle: others work hard, while the Host takes it easy. “I have a rare spirit root that appears only once in a century, and my cultivation speed is incredible.” Sorry, I’m only twice as fast as you. “I have a Heavenly Spirit Root, a once-in-a-millennium talent, and my cultivation speed goes whoosh!” I’m really sorry, yours is only half of mine. From then on, while everyone else devotes themselves to cultivation, Song Rui enjoys a very different life. While eating, his cultivation improves at double speed; while walking, his cultivation improves at double speed; even while taking a dump, his cultivation is still improving at double speed. And so, Song Rui secretly resolves: During my growth period, I’ll keep my head down and stay out of trouble; once I’ve matured, I’ll look down on the world and roam wherever I please...