In Greek mythology, the Keres (singular: Ker) were female death-spirits. The Keres were daughters of Nyx, and as such the sisters of Fate (Moirae), Doom (Moros), Death and Sleep (Thanatos and Hypnos), Strife (Eris), Old Age (Geras), Divine Retribution (Nemesis), Charon, and other personifications. Some, such as Cicero who calls them by a Latin name, Tenebrae, or the Darknesses, name them daughters of Erebus and Nyx.

They were described as dark beings with gnashing teeth and claws and with a thirst for human blood. They would hover over the battlefield and search for dying and wounded men.