The Ini-Ma manifested in different women through several centuries on Earth. Some of her incarnations included Leaf Snakeskin, Panatos Jones, Susannah Hunter, Martha Barrett, Lucinda Addison and Loretta van Cheaden.
When Sebastian Malvern, to whom Lai-Ma's brother Tko-Ma had connected, suspected the Cylox' true intentions, he had the Magnate's ESPnets drain the energy from Tko-Ma's dimension. The Sixth Doctor convinced him to entrap himself in a fragment of the dimension to save himself. The Doctor then gave the fragment to the Ini-Ma so she could trap the brother as well.
What the Doctor did not realise was that the Ini-Ma was really the jailer of the two Cylox. Rather than risk them trying to escape again, she unleashed energy to destroy herself and them. (PROSE: Instruments of Darkness)