10 Disturbing Backstories Behind Doctor Who Characters

When the Doctor entered into the Time Lord Academy, they met their closest friend, the Master. In many ways, the Master and the Doctor are two sides of the same coin. Where the Doctor is compassionate and contemplative, the Master is ruthless and evil, but they have more in common than they care to admit.

The Master has been at the center of many of the plots meant to kill or destroy the people the Doctor holds dear. They're considered a renegade among the Time Lords, but more than that, they're irretrievably insane, resulting from something they call "the drums."

This was a four-note drum beat that plagued them. The sound was instilled within their mind when they gazed into the Untempered Schism as a child. From that point, the drums continued to worsen throughout their life, and no matter what they tried, they couldn't run away from them.

Much of the Master's life has been structured by this unique form of insanity, which has pushed them to slaughter countless people across time and space. Their main goal is to kill the Doctor, but it's also something they're unwilling to do because they knows if they ever did, the Master would truly be alone in the universe.