In Greek mythology, the Keres /ˈkɪriːz/ (Κῆρες), singular Ker /ˈkɜːr/ (Κήρ), were female death-spirits. The Keres were daughters of Nyx, and as such the sisters of beings such as Moirai, who controlled the fate of souls and Thanatos, the god of peaceful death. Some later authorities, such as Cicero, called them by a Latin name, Tenebrae, or the Darknesses, and named them daughters of Erebus and Nyx.
The Greek word Kir or Ker ( κήρ ), means goddess of death, or doom. Homer uses the word with this meaning κήρες θανάτοιο , "goddesses of death", or meaning "violent death". By extension the word may mean "plague, disease" and in prose "blemish or defect". The relative verb κεραίζω or κείρω means "ravage or plunder". Sometimes in Homer the words "ker" and moira, have almost similar meaning. The older meaning was probably "destruction of the dead", and Heshychius relates the word with the verb κηραινειν, "decay".
And Nyx (Night) bare hateful Moros (Doom) and black Ker (Violent Death) and Thanatos (Death), and she bare Hypnos (Sleep) and the tribe of Oneiroi (Dreams). And again the goddess murky Nyx, though she lay with none, bare Momos (Blame) and painful Oizys (Misery), and the Hesperides ... Also she bare the Moirai (Fates) and the ruthless avenging Keres (Death-Fates) ... Also deadly Nyx bare Nemesis (Revenge) to afflict mortal men, and after her, Apate (Deceit) and Philotes (Friendship) and hateful Geras (Old Age) and hard-hearted Eris (Strife).
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. A description of the Keres can be found in the Shield of Heracles (248-57):