Rosata Laxter

 was a former soldier turned smuggler. She told the War Doctor about the Lady of Obsidian and took him to the Nebula. Her ship was taken by The Unlived and she escaped with the Doctor. She was found by Leela who told her about those creatures. when Skaul came to the ship she helped to defend the Doctor when he closed the breach. She died due to proximity to the time breach. (AUDIO: The Lady of Obsidian)