After Testing Medicine for a Hundred Years, I Became a Master of Magic

Those who become enlightened must take great medicine. However, the world is unkind and regards all things as stupid dogs. Great medicine also contains great poison. Before taking medicine, you must test the medicine first. Luo Xia entered the Immortal Sect and thought he would embark on the road to immortality, but he was told that with his talent, he could only be a drug boy! After taking a large amount of medicine, he unexpectedly found a sky-swallowing toad in his body, which should have turned into blood and pus in three days. From then on, the poison became a great tonic. Not only that, his bones, cultivation, and life span all underwent earth-shaking changes. Hundreds of years have passed, and a real demon is hidden under the entrance of the Medicine Testing Peak! He covered the sun and moon with dark clouds, and covered the universe with his two sleeves of canopy: "From now on, the path of immortality and the path of demons are all mine!"