In the Epitaph of Twilight, the Cursed Wave is the name of the malevolent force that seeks to destroy the world. In order to destroy the Cursed Wave, they send two half-sprites (which cast a shadow) and a human to the Wavering Peninsula at the Edge of the World, accompanied by Fili the White and Bith the Black along the way. Spoiler warning: Plot and/or ending details follow.