Doctor Who: 8 Reasons The Tenth Doctor Was An Actual Monster
6. The Entire Family Of Blood Saga
The Family of Blood were intimidating aliens who came after the Doctor, desperate to steal his Time Lord life force to allow themselves to live. The Doctor takes Martha to a quiet village in England in 1913, where he hides his Time Lord essence in a fob watch and leaves her with instructions to keep him safe until the Family die off.
The Family follow the Doctor to Earth and discover the village where he's hiding. As they search for him, they murder innocent people indiscriminately, including a young child. Meanwhile, the Doctor has fallen in love with Joan, and their relationship escalates quickly. None of this would have happened if the Doctor had fought the Family head-on.
Eventually, the Doctor is forced to tear Joan's heart out with the truth, before he leaves to punish the Family. We really see his cruel streak here. In retaliation for their violence, he sentences each of them to the most brutal of punishments. The Family wanted immortality, and the Doctor gave them that in the most inconvenient and horrible ways. One is imprisoned in a mirror, one on the edge of a collapsing galaxy and others bound in unbreakable chains and tied up to remain a scarecrow.
Let this be a reminder to not get on Ten's bad side.