The adopted daughter of an anime otaku, she was expecting a baby brother when her arc begins.
Her battle begins the night after her mother enters labour. During the battle, she discovers that the robots that they have been fighting are in fact piloted by humans of Alternate Universes, and that the battles are the method for choosing which ones survive, and which ones don't. With every victory, 10 billion people from another universe die. As she finishes her battle, she uses Zearth's powers to see the birth of her baby brother. In the manga her chair is a baby cot, but is changed to a rocking chair in the anime version. Later is revealed that Maki's family was not informed of her fate, and continue to look for her hoping that she may be alive.