History of the book that gave rise to Shin megami Tensei:

Akemi Nakajima, of the school's gifted class and a computer genius, is assaulted by Hiroyuki Kondo of the normal class under the orders of Kyoko Takamizawa, who had been angered by Nakajima rejecting her romantic advances. Kyoko had told Kondo that Nakajima had been flirting with her rather than the other way around, prompting the attack.

The normal students were rarely punished for their actions against other students out of fear and pity on the part of faculty. Battered and bloody, Nakajima comes home and decides to finish his Demon Summoning Program, a work in progress of his, to exact revenge. He discovers that his computer is not powerful enough to use the program, so he must use the school's Computer Aided Instruction (CAI) room's host computer.

Sneaking into the school at night, Nakajima draws a pentagram in the computer room and attempts to run the program, but is found by Professor Iida. Nakajima has a tense conversation with the professor, who becomes afraid of him, but he is able to run the program regardless. Nakajima commands the program to kill Kondo and Kyoko, which causes a tremor in the school but otherwise appears to not work.

A week later while Professor Iida is teaching a computer class in the CAI room with Nakajima and Kyoko present. Suddenly a voice resounds from the host computer. A demon, Loki, trapped inside the host computer, uses the monitors in the CAI room to hypnotize the entire class except Nakajima, Kyoko and Professor Iida. The demon follows Nakajima's request and commands the hypnotized students to kill Kyoko. They then lure Hiroyuki Kondo, into the room and kill him as well. Professor Iida is also killed in the chaos, which upsets Nakajima somewhat: Loki had followed the program's command, but Nakajima had not specified any restrictions.

Drunk with power, Nakajima at first begins to comply with Loki's request for female sacrifices, offering him his female professor, Ohara, who proceeds to be metaphysically assaulted by Loki through the use of a helmet-like contraption connected to the summoning program. Permanently damaged by the encounter, Ohara eventually becomes Loki's loyal servant and helps Loki assume physical form in the human world through Nakajima's program as well as her own connection to the demon.

Nakajima meets Yumiko Shirasagi during this time, a newly-transferred student with whom he feels a strange connection to. Unbeknownst to him, she had witnessed the bizarre encounter with Ohara and Loki, but had dismissed it as illusion and trickery. Eventually, the demon demands that Nakajima offer him Yumiko, which Nakajima refuses to do. He then advises Yumiko to stay away from the school in an attempt to save her. That night, Yumiko ignores Nakajima's advice and returns to the school, prompting the attention of Loki. Nakajima attempts to regain control of Loki, but the demon mocks Nakajima's attempts to command him.

Loki summons himself into the physical world through the CAI room computer and goes on a killing spree, free from Nakajima's control. Jealous of Yumiko, Ohara attacks and wounds her. Nakajima summons a benign, loyal demon, Cerberus, to help him battle Loki, to no avail. During the battle, Yumiko is possessed by Izanami, of whom Yumiko is a reincarnation, and burns Loki with her powers. In addition to dealing with Cerberus, Loki is distracted enough so that Yumiko and Nakajima can escape through a dimensional warp to Asuka created by Izanami, although Loki succeeds in fatally wounding Yumiko as she flees.

Still influenced by Izanami, Yumiko tells Nakajima that she will die, but could be revived if her body is brought to Izanami's tomb. Yumiko dies, but with the help of Cerberus, Nakajima complies with her dying request and travels to the Shirasagi Mount, where he meets Yomotsu-Shikome, a loyal servant of Izanami's.

Yomotsu-Shikome provides Nakajima with two mystical spheres, and guides him onward. With Ohara's help, Loki is able to follow them to Asuka and Shirasagi Mount, where he kills Yomotsu-Shikome. Izanami meets Nakajima and Yumiko in the tomb, but she is attacked by Loki before the resurrection can take place. Nakajima summons Cerberus to help, but his companion is also no match for Loki, and is defeated. Desperate, Nakajima uses the two spheres that Yomotu-Shikome gave him, which ignite the pomade-covered floor of the tomb, summoning Hinokagutsuchi, who in turn transforms into a powerful, mystical fire sword, with which Nakajima is at last able to kill Loki. Izanami succeeds in reviving Yumiko, but keeps her with her, stating that Yumiko has great hidden powers within her with which they could battle evil.

Meanwhile, Ohara, impregnated by Loki, attempts to communicate with him, not knowing that he has perished. This makes her accidentally contact the demon Seth.