Eternal Darkness: Sanity's Requiem is a psychological horror action-adventure video game developed by Silicon Knights and published by Nintendo. Originally planned for the Nintendo 64, it was made a launch title for the GameCube and released on June 24, 2002. While the game features similar gameplay mechanics to that of the Resident Evil series, it distinguishes itself with unique features, such as "sanity effects". In the game, players take on the role of several characters, including a young female American student who is forced to return to her family's mansion in Rhode Island to investigate her grandfather's murder, as they become embroiled in a struggle against a powerful entity and their servant who seek to enslave humanity.
Eternal Darkness was not a commercial success following its launch, but was widely praised by reviewers and won numerous awards. Although a direct follow-up to the game was cancelled by Nintendo, who owned the game's copyright, and Silicon Knights later went bankrupt and disbanded, the game's writer and director Denis Dyack has been attempting to make a spiritual successor entitled Shadow of the Eternals.