Reborn into Grass, Signed into World Tree at the Beginning

Lu Fan was reborn as a weed, but fortunately, he awakened to the sign-in system and signed into the World Tree at the beginning. That spiritual tree, I think you are suitable to be my sect's mountain spiritual tree; That spiritual tree, I think you are suitable to be the material for my magic weapon; That spiritual tree, I think you are suitable to be the firewood for my alchemy furnace; That spiritual tree... In the cruel world of immortality, those who have no strength can only become the magic weapon and spiritual beast of the enemy. Lu Fan encounters demons and subdues demons, encounters immortals and slays immortals, conquers three thousand worlds, and becomes a generation of immortal emperors!