Nyssa of Traken or Nyssa, Daughter of Tremas, oftenly simply Nyssa, is a companion of the Fourth and Fifth Doctors. She is born on the planet Traken, capital of the Traken Union. Nyssa has a privileged upbringing, being the daughter of Consul Tremas and Traken nobility. After witnessing the destruction of the entire Traken Union and becoming the last of her kind, Nyssa starts travelling with the Doctor. In one of their travels, the TARDIS lands on the space station Terminus, which they find out to be a leper colony, and Nyssa contracts the disease. She decides to leave the Doctor to stay in the space station, hoping to help free the enslaved guards and turn the station into a real hospital.