Summary
TheEternal DarknessSanity System patent has expired and is now in the public domain, meaning anyone can use the system—though there’s a catch. There are several reasons whyEternal Darknessis considered a cult classic among fans, and one of them is definitely its Sanity System, which was a Nintendo property.
Eternal Darknesscame out in 2002 for the Nintendo GameCube and has never been officially ported to another platform. In fact,Eternal Darknesscan’t be purchased anymore, as the classic title was left for dead once the GameCube was discontinued. And although it’s regarded as a cult classic, there has been no effort from Nintendo to preserve the game. It offered a horror action-adventure experience with a little twist to the survival-horror formula, following the story of a college student after the murder of her grandfather. The story spanned different time periods, including ancient Rome and medieval France, though a hallmark of the game was its Sanity System, which caused the character to hallucinate when her sanity levels dropped.
Taking to Reddit, user DocMemory noticed a while ago thatNintendo’sEternal DarknessSanity Systempatent had expired, raising the question of whether anyone can now use it themselves. The initial expiration date was Jun 01, 2025, but it now reads “Expired – Lifetime,” suggesting that the infamous patent on the Sanity System has belonged to the public since then. To clarify the matter,Eurogamerspoke with video game legal expert Richard Hoeg and, according to the lawyer, anyone can use any element of the system that is “necessary” to its function. However, it is not possible to use things that are not necessary, such as graphics or specific sanity effects, since “that’s artistic expression rightly protected by copyright,” Hoeg said.
Anyone Can Now Use Eternal Darkness’ Iconic Sanity System
The Sanity System is likely one of the thingsplayers miss most fromEternal Darkness, and now anyone can implement the system as long as they don’t directly copy elements of the game. For those who don’t remember it well, the system was all about the character slowly losing their sanity after seeing things like “game creatures or gruesome situations.”
As the sanity decreased, the character would start to hallucinate, and the game would introduce disturbing effects—such as visual distortion, whispers, or even simulated system errors that pretended to delete the player’s saved data—all of which effectively involved the player in the character’s madness. Even thoughEternal Darknessremains trapped on the GameCube, the former director said a while ago he’d like to see a remaster. While nothing has been announced regarding this, at least developers can now use the infamous Sanity System in their own games.
