"A stalker of Eriko... He has a criminal history, including breaking into her house."
—Persona 2: Eternal Punishment introduction
The stalker appeared before Eriko Kirishima when she started her modelling career. His behavior became more and more extreme to the point that in one day he broke into Eriko's apartment before she was home. Irritated, she used her Persona to fight him off and supposedly the stalker had learned his lesson and no longer showed his face.
If the player chooses Eriko's route, the party will accompany Eriko to Sumaru TV to investigate Chizuru Ishigami. When they are trapped in Ishigami's puzzle and trying to solve it, the stalker appears before them three times with a chainsaw, and is defeated each time. It is later revealed that the stalker here is merely a Shikigami sent by Ishigami to embody Eriko's fear.
Although possibly a programming error, during the first and second battles the stalker always attacks Baofu, and Katsuya in addition during the third battle when shouting "Elly-chan" and "I love you", except for attacks that target everyone.
The harassment prevention regulation has been passed in 2000 in Japan after a female was murdered by her stalker. That means there was no law to protect the victim from stalking prior to that year.