La Muerte is the Goddess of Death and the Queen of the Land of the Remembered. She is the sister of La Noche and the estranged wife of Xibalba. Before meeting Xibalba she was El Chamuco's love interest/ lover.
Book Of Life (2014)
Although La Muerte and Xibalba deeply loved each other, they have complicated relationships due to their different perspectives towards humanity. La Muerte views humanity positively, while Xibalba views humanity negatively. Xibalba may look evil, but not for La Muerte she still believes in goodness that still exists in Xibalba. In the end of the movie, they reunited by kissing each other.