After being given new armor and weapons by Artakha, the Toa Nuva arrived at Karda Nui, the core of the universe. There, they came to face the Makuta who were trying to turn the population of Av-Matoran – Matoran of Light – into Shadow Matoran. The Toa Nuva were helped by the arrival of Takanuva, now able to control Light and Shadow because of a shadow leech attack, and Toa Ignika, who is the Mask of Life itself. The Kanohi Ignika had made a body for itself because it wished to see what it was like to be a living being. With their combined forces, they reached a structure in the center of Karda Nui called the Codrex, where Toa Ignika had to sacrifice his new body to awaken Mata Nui. Takanuva, with the help of the remaining uncorrupted Av-Matoran, returned the Shadow Matoran to their previous states. Shortly afterwards, the Toa escaped the core before the energy storm caused by Mata Nui's awakening could destroy them. The Makuta, however, failed to escape, and were all killed. Back in Metru Nui, Mata Nui's awakening was celebrated, but celebration was cut short when it was revealed that Teridax had taken over the body of Mata Nui, revealed to be the universe of the Matoran. Trapping the spirit of Mata Nui in the Mask of Life, he sent it flying into space so that the former Great Spirit cannot interfere with his control over the universe.