This topic might have a better name.
Sesha since it is spelled that way in the script.
Talk about it here.
Seksa was the daughter of Anulf. After his disappearance she became the leader of a band of survivors from a crash on Chodor. Her stepmother Mertil didn't agree with her being the leader. In order to frame the Fifth Doctor and Tegan Jovanka, Mertil murdered her after revealing she killed her mother. (AUDIO: The Whispering Forest)
Behind the scenes
The script given to download subscribers has her name as Sesha, which is exactly what you hear in the story.