The
Greek poet Hesiod established in his
Theogony that Thánatos has no father, but is the son of
Nyx (Night) and brother of
Hypnos (Sleep).
Homer earlier described Hypnos and Thanatos as twin brothers in his epic poem, the
Iliad, where they were charged by
Zeus via
Apollo with the swift delivery of the slain hero
Sarpedon to his homeland of
Lycia. Counted among Thanatos' siblings were other negative personifications such as
Geras (Old Age),
Oizys (Suffering),
Moros (Doom),
Apate (Deception),
Momus (Blame),
Eris (Strife), and
Nemesis (Retribution). Thanatos was loosely associated with the three
Moirai (for Hesiod, also daughters of Night), particularly
Atropos, who was a goddess of death in her own right. He is also, at times, specified as being exclusive to a peaceful death, while the bloodthirsty
Keres embodied violent death. His duties as a
Guide of the Dead were sometimes superseded by
Hermes Psychopompos. The god's character is established by
Hesiod in the following passage of the
Theogony: Thanatos was thus regarded as merciless and indiscriminate, hated by – and hateful towards — mortals and gods alike. But in myths which feature him, Thanatos could occasionally be outwitted, a feat that the sly King
Sisyphus of
Korinth twice accomplished. When it came time for Sisyphus to die, Zeus ordered Thanatos to chain Sisyphus up in
Tartarus. Sisyphus cheated death by tricking Thanatos into his own shackles, thereby preventing the demise of any mortal while Thanatos was so enchained. Eventually
Ares, the bloodthirsty god of war, grew frustrated with the battles he incited, since neither side could suffer any casualties. He released Thanatos and handed his captor over to the god. Sisyphus would evade Death a second time by convincing
Persephone to allow him to return to his wife stating that she never gave him a proper funeral. This time, Sisyphus was forcefully dragged back to the Underworld by
Hermes, where he was sentenced to an eternity of frustration in Tartarus, rolling a boulder up a hill only to have it roll back down when he got close to the top. A fragment of
Alcaeus, a Greek lyric poet of the 6th century BC, refers to this episode: . As the son of
Aeolus (and thus a descendant of the Titan
Prometheus), Sisyphus was a more-than-mortal figure: when it came to ordinary humans, Thanatos was usually thought of as inexorable. The sole time he was successfully prevented from claiming a mortal life was by the intervention of the hero
Heracles, a son of
Zeus. Thanatos had come to take the soul of
Alkestis, who had offered her life in exchange for the continued life of her husband, King
Admetos of
Pherai. Heracles was an honored guest in the House of Admetos at the time and offered to repay the king's hospitality by contending with Death itself for Alkestis' life. When Thanatos ascended from
Hades to claim Alkestis, Heracles sprung upon the god and overpowered him, winning the right to have Alkestis remain, while Thanatos fled, cheated of his quarry.
Euripides, in
Alcestis: == In art==