The Megami Tensei series (女神転生?, lit. "Goddess Reincarnation") is the first series of games that comprise the Megami Tensei franchise. Being the first they have been influential to the franchise as a whole, introducing a first person perspective while exploring labyrinths, the gathering and fusion of demons, as well as the concept of moon phases. The first game is based on the novel by Aya Nishitani called Digital Devil Story: Megami Tensei, but subsequent games and series would stray from the novels. The name of the series is from the character Yumiko Shirasagi, as she is the titular "Megami Tensei" (Goddess Reincarnation) and was the reincarnation of Izanami. Future games would keep the title in some form, even without a reincarnation within the story.