According to one account, Qin Shi Huang rescued an alien from the wreckage of a "star chariot" when he was a boy. He came to know the alien as his first general and most trusted advisor, Meng Tian. Using Meng's knowledge, Qin Shi Huang united the Warring States, making him the First Emperor. Following a failed assassination attempt, Qin Shi Huang had Meng build him a new, indestructible body, making him a cyborg. He also sought immortality.
Meng, seeking to take control of Earth, later remotely activated the Terracotta Army, and switched off Qin Shi Huang in his throne room, describing him as a puppet who had outlived his usefulness. Donna Noble used her mobile phone to interrupt the signal paralysing the Emperor, waking him up again. While Qin Shi Huang and Meng were fighting each other, Meng shot at the warp converter, which shut down the Emperor and the Army, while also burying the whole palace in an explosion. According to the Tenth Doctor, no-one knew how he died. (COMIC: The Immortal Emperor)
In 1289, Marco Polo told Barbara Wright that Emperor Qin Shi Huang had started the tradition of protecting the ruler of China with imitation soldiers, having had 6000 made to protect his tomb. At this time, no one knew where his tomb was located, however the First Doctor slyly suggested they dig around Xian, where the capital had been. (PROSE: Marco Polo)