Doctor Who Companion Profile: Nyssa
Nyssa is the princess of Traken, a planet that comes under the attack of the Master and is eventually completely destroyed, making her the sole Trakenite in the universe. In her first two stories, first her stepmother and then her father are killed, and finally her planet is eaten by a wave of entropy that threatens the entire universe. Consequentially, the Fifth Doctor takes her in, determined to protect and guide her.