While game developer Square was known primarily for their various fantastical role-playing games (namely Final Fantasy) in the 1990s, they took a chance in a different genre with Parasite Eve. The game, which debuted in March 1998 in Japan before coming to the U.S. in September of that year, married Square’s solid footing in RPGs with some truly creepy horror elements for a memorable experience.

Parasite Eve the video game is actually a sequel to the 1995 novel Parasite Eve by Hideaki Sena. The story follows Aya Brea, a rookie NYPD officer, who is investigating a series of mysterious and deadly events surrounding an entity known only as “Eve.” Eve’s first act against humanity is to cause an opera house full of people to spontaneously combust; Aya, who is in attendance, somehow escapes unharmed, but is told by Eve that her mitochondria need to develop more. It is eventually discovered that Eve can control the mitochondria (the powerhouse of the cell) in people’s bodies in order to change their form, control them, or kill them. Aya and Eve have advanced forms of mitochondria that are considered the next step in human evolution – however, Eve wants to use these powers in order to create “ultimate beings” to replace humanity entirely.

The game was Square’s first foray into M/Mature-rated content, and it was received positively by consumers. The mashup of RPG mechanics with a horror-focused story helped it to stand out, and the game eventually sold nearly 2 million copies worldwide. Parasite Eve eventually received two sequels: Parasite Eve II in 1999, and The 3rd Birthday in 2010.

Parasite Eve is credited with helping to popularize Japanese horror around the world during the time of its release, along the same lines of popular films such as The Ring.