Elder Sign is a cooperative card and dice game, based on the Cthulhu Mythos of horror writer H.P. Lovecraft and Chaosium's Call of Cthulhu roleplaying game. It is published by Fantasy Flight Games, which also produces the Cthulhu Mythos games Arkham Horror, Call of Cthulhu: The Card Game, Mansions of Madness, and Eldritch Horror.
Giaco Furino of Fearnet wrote, "If you're a Cthulhu fan this game is a must." Michael Harrison of Wired.com called it "a fun, thrilling dice game".
An expansion called Unseen Forces was released in 2013. It introduced the Blessed/Cursed mechanic. Two new dice were added - a player uses the white die when they are Blessed and the black die when they are Cursed. The Blessed die has the same sides as a green die and its result can be used to help complete adventure card tasks. The Cursed die also has the same sides as a green die but instead of using its result to aid you, if it matches the result of another die that was rolled, both dice are removed for the remainder of the adventure, making it harder to complete it. The expansion also added many new cards to the game, including optional Master Mythos cards that can be used to increase the difficulty of the game.
A second expansion called Gates of Arkham was released in 2015. It introduced a new game mode called 'Streets of Arkham' which completely changes the way the game is played. Instead of always having adventure cards face up, they are face down, adding a completely new unknown element to the game. There are ways to flip cards over, but typically, each player explores the streets of Arkham at their own risk, not knowing what tasks will be required to complete an adventure until the player has already committed to it. This, along with other elements, such as gate openings, make the game significantly more difficult than the normal game mode.