Twilight

Twilight is matter originating from the Twilight Realm that plagued Hyrule 100 years after the events of The Legend of Zelda: Ocarina of Time in The Legend of Zelda: Twilight Princess.

The Twilight King, Zant, was granted this power by Ganondorf in exchange for freedom from the Twilight Realm (he was sent there after surviving his death sentence.)

Eventually, Link restored power to the light spirits of Hyrule, cleansing the land. The twilight was stopped for good with the death of Zant.