Thanatos is death itself given a face, not the manner of dying but the fact of it. In Hesiod's Theogony he is a child of Nyx, Night, born without a father, and the twin brother of Hypnos, Sleep; the pairing is exact, for the Greeks felt death and sleep to be near neighbours. Homer shows the two brothers together in the Iliad, where at Zeus's command Sleep and Death lift the body of the fallen hero Sarpedon and carry it gently home to Lycia for burial. That gentleness distinguishes Thanatos from the Keres, the fierce spirits of violent slaughter on the battlefield: he is the quiet, inevitable close rather than the bloody one. In folktale he could even be cheated for a time, the cunning Sisyphus was said to have bound him, so that no one could die until he was released, but such stories only underline that death, in the end, is not to be evaded.
Thanatos receives his fullest treatment on the Greek stage in Euripides' Alcestis (438 BCE), where he appears as a speaking character who comes to claim the queen Alcestis after she has agreed to die in her husband's place; the hero Heracles, arriving as a guest at the house of mourning, ambushes Thanatos at the tomb and physically wrestles Alcestis back from him by force, one of the few surviving Greek tragedies in which Death himself is a character on stage, and the only one in which he is bested by main strength rather than persuasion or trickery.