Waywalker

 was a young inhabitant of the planet the Fifth Doctor and Vislor Turlough visited. She went to collect an ambricore to start a right of passage. The Doctor and Turlough saved her from falling but they were all caught in a landslide. She was rejected from finding her path as she wanted to remember the Doctor's and Turlough's voice. Before her transformation she warned her people about how they must change their ways to survive. (AUDIO: The Becoming)