An evil and sentient darkness born from the Demon King himself which plays a central role in The Legend Of Zelda: Breath Of The Wild and its respective sequel and spin-offs. Referred as Gloom in Tears of the Kingdom.
It usually manifest as a slugde or miasma capable of corrupt and damage anything it touches or can assume physical forms like disembodied eyes, tendrils, hands and even form beings composed entirely of this substance.