Thilma is a flying monkey and one of four who travelled from Oz to Maracoor Abiding to rescue Rain and Cossy from the Maracoor Crown prison and later assist them in travelling to find the Oracle of Maracoor. She is the most intelligent of the flying monkeys who travel to Maracoor, and unlike her companions' Tiotro, Faro, and Finistro, she can speak, although in partial broken grammar.
She returned to Oz after Lucikles had gotten back to High Chora after seeing Rain off. Tiotro and the others did not make the journey back, however, as they feared having to fly over the ocean again. Thilma would later converse with Nanny at Kiamo Ko, catching her up about everything that had occurred in Maracoor.