The Sycorax appeared in “The Christmas Invasion”, the 10th Doctor’s first full episode.
The Sycorax’s language is “Sycoraxic”. Through Blood Control the Sycorax take control over one third of the population, the people with A+ (A Positive) blood, controlling them to climb to the highest spots they can and stand right at the very edge as if they were to jump.
They can control the A+ blood as it was a sample on the “Guinevere One” probe that UNIT (United Nations Intelligence Taskforce) sent out to space which collided with their ship. On the space probe there was a sample of A+ blood and from that they control the blood. The Sycorax say their armada is permanently in orbit around the Jewel of Staa Crafell.
The Sycorax claim Earth as their own planet and threaten that if the human race isn’t sold into slavery then they will kill the one third of the population with A+ blood.
Among the many Sycorax, is the Sycorax Leader (Can be seen below).
The Sycorax Leader is in control of the other Sycorax and has a whip which kills people. An electric force surrounds the whip when used and turns a human to skull and bone, a skeleton. In “The Christmas Invasion” , The Doctor and the Sycorax Leader challenge each other to a sword fight, for the planet. When The Doctor is victorious he gives the Sycorax and Sycorax leader a chance to flee and leave Earth alone, however the Sycorax leader runs behind The Doctor, just about to attack him when The Doctor throws a Satsuma at a orange button on the Sycorax ship, making the Sycorax Leader fall to his death.
The Sycorax however are given a chance to flee and tell others of the planet and its goods, its riches and of what happened, and to never attack again. While fleeing, Harriet Jones commands Torchwood to fire four beams into the sky, which ended up killing the Sycorax aboard that ship.. In “The Shakespeare Code” the Sycorax are mentioned by The Doctor when he picks up a horse like skull and says “It reminds me too much of the Sycorax”. Shakespeare then said “Sycorax, I might use that” and eventually he did Sycorax was a name of a witch in “The Tempest”, one of Shakespeare’s plays.
The Sycorax's average individual lifespan is 400 years, they come from the planet “Firetrap (JX82 System)” where some Sycorax may still live. It is far from the end of the Sycorax race.