Shas-Raklat was a Dreamspinner and an outcast from her own race, the Menim, having had her sight removed as punishment. She arrived on Karagula appearing as a woman in blue. She promised to make the surface dwellers “hearts desires come true.”
Having lost her sight, she developed her own olfaction (sense of smell) through the use of technology grafted into her head, to such a high level that she was able to emit odours through synthesising her own odours and the use of expertly crafted odours to have a calculated and unique effect on those around her and, including the Karagulans.
Such was her skill that she could alter memories, create visions and stimulate pleasurable emotions. In exchange for her "smells" the Darksmith Collective allowed her to take the children from the Karagulan surface dwellers for their olfactory spare parts.
She spent three days amongst the people before changing their world on the fourth day. Altering their collective memory of the past to create a "desirable" present (which in effect remained unchanged), she was able to name her price – the children.
Using a Black Incense trance, the children obediently followed her back to the Dark Cathedral. She wore the black flame design of the Darksmiths inlaid in a rough stone that made the Karagulans fearful to displease her.
When the Tenth Doctor, aided by Bethin and Lorton, freed the children, they also took her spacecraft and left her with the Darksmiths. (PROSE: The Colour of Darkness)