Doctor Who: 9 Worst Things The Master Has Ever Done

David Tennant's swan song saw the return of his arch nemesis, with the Master once more brought back to life. However, this time with a more Skeletor-like appearance.

Asked to mend a device called the Immortality Gate, the Master obliges in order to use it for his own purposes. As always the Master is on a quest to extend his life, and restore himself back to full health.

So how does he do that? Well, just turned every human into him, of course. 'Cause what else would you do.

With this act, the Master literally has an army of 6 million versions of himself, all with his mind. Using this increased mental power, the Master seeks out the cause of the drumming in his head. With this, he makes contact with the High Council of Gallifrey and is able to breakthrough the time lock into the Time War.

It doesn't even bare thinking about, a universe with six million Masters taking control. This situation is made even worse by the fact he hijacks the human race, basically using them all as his puppets for his own ends.

If not for one of the most powerful Time Lords to ever exist, Rassilon, this could easily have been it for Humanity.