Tobias Vaughn was the managing director of International Electromatics, the world's leading electronics company.
Vaughn made contact with the Cybermen, formed an alliance with them, and then masterminded an invasion of Earth in return for a share of the power. However, these plans fell apart when the Cybermen thought he betrayed them. Allying himself with the Second Doctor, and, using an invention that induced extra-strong emotions deadly to Cybermen, he helped the Doctor to defeat them. He was killed on a rooftop after being shot by a Cyberman. (TV: The Invasion)
At the moment of death, Vaughn's consciousness was transmitted via satellite into one of fourteen identical robot copies of himself. Over the years, he influenced and manipulated humanity's development. He invested the remains of International Electromatics' empire into new technologies, such as the BOSS supercomputer, the development of the Time Scoop, and Professor Kettlewell's inventions. As the Cybermen repeatedly attempted to invade Earth, Vaughn bought pieces of their technology in order to repair his failing body with what was left of his money.
In the 30th century, Vaughn encountered the Seventh Doctor. Vaughn captured the Doctor, hoping to learn the secret of time travel from him. The Doctor trapped Vaughn in the TARDIS, preventing him from transferring his consciousness to another body. The Doctor later removed Vaughn's brain crystal and installed it in a food machine. (PROSE: Original Sin)