Also known as: デジタル・デビル・ストーリー女神転生, デジタル・デビル物語女神転生
The first entry in the Megami Tensei series, released in 1987. It is an adaptation of the book "Digital Devil Story: Megami Tensei" in the form of a first-person RPG. It would be followed up by Megami Tensei II in 1990, which would be partially remade in the form of 1992's Shin Megami Tensei I, setting in stone the brand and series from then on.
Megaten I and II would also see an enhanced Super Famicom port in 1995, entitled Kyuuyaku Megami Tensei.