Crystalis is a 1990 action role-playing action-adventure video game produced by SNK for the Nintendo Entertainment System. The game's initial success prompted an enhanced port for the Game Boy Color by Nintendo Software Technology in 2000. Many changes were made to the story, music, and other aspects of the game, upsetting fans of the original.

The game begins with a young magician awakening from the cryogenic sleep he was placed in by the villains of the Great War before nuclear war rained down in the year 1997. Even though he is unable to recall his name or who he was, he exits the Mezame Shrine and discovers that he may be the key to save this world from destruction. Aided by four wise sages and a mysterious woman, he rises up against the tyrannical Draygonian Empire to ensure that humanity ultimately does not repeat the Great War.