After completing the game once, the player can access the Chrysler Building and have access to the true final boss, who takes the form of Aya's sister, Maya. She explains to Aya that Klamp cultivated the liver cells of the original Eve to analyze. When Melissa was giving birth to the Ultimate Being, she created a nest there. In case Melissa and the Ultimate Being failed, the purebred would remain. Aya speaks with her sister, and they engage in battle against the purebred. After the purebred is defeated, the mitochondria inside Aya's body begin to rebel against her. It is explained that Aya's mitochondria have now reached a higher evolutionary stage than Maya's, but Maya's personality has suddenly become dominant and begun to fight off the Eve persona. Maya eventually wins, purging the Eve persona from herself. Somehow, Maya protects Aya by preventing the original Eve from taking over her. Aya leaves the building by herself, although she apparently has gained some sort of connection with her dead sister.