Immortal Qin

After waking up as Xu Fu, the protagonist immediately offers an eternal life pill to Qin Shi Huang. Breaking all conventions, he gets struck by lightning and dies, only to discover a shocking truth: Earth is actually a giant prison. Upon resurrection, Qin Shi Huang demands the source of the elixir. Bluffing that it comes from a mystical realm, the protagonist is shocked when the emperor slams his table and declares it was once a lost territory of Qin. In a moment of panic, he hastily teaches modern cultivation techniques to the Qin army, only to find they truly ascend to immortality. From then on, the protagonist leads Qin Shi Huang to conquer the cultivation world, aiming for the supreme throne.