The Immortal of Plague begins by establishing the root of lung fire.

Birth, aging, sickness, and death—these are feared by mortals; a hundred ailments are sought by immortals. In this world, the immortal sects do not accept the healthy, but only those with deeply rooted illnesses. In his past life, he was a healer, saving lives and healing the wounded; in this life, he is a disciple, taking illness as his path. Medical student Song You's soul transmigrates here, forced to cultivate the [Lung Fire Dao Root], embarking on a completely different path of cultivation. Lung fire burns his body, bone marrow ulcers penetrate, blood plague rages, and soul plague erodes his spirit—the world sees illness as an omen of misfortune, but I alone see it as a great medicine. Using my body as a cauldron, I absorb countless ailments, refine an unparalleled Dao body, and become a plague immortal.