Hypnos is the god who personifies sleep and is the brother of Thanatos.
In Greek mythology, Hypnos embodies sleep as a divine power rather than merely ruling over human rest. His twin brother is Thanatos, the personification of death. Both are associated with the underworld, and ancient tradition often presents them as closely linked forces: sleep resembles a temporary death, while death is sometimes described as eternal sleep.
Hesiod names Hypnos as a child of Nyx, the goddess of Night, and in some later genealogies his father is Erebus, personification of darkness. Hypnos is also connected with Pasithea, one of the Charites. In Homer’s Iliad, Hera persuades him to put Zeus to sleep so that the Greeks can gain an advantage in the Trojan War.
Hypnos is commonly confused with Morpheus, Phobetor, and Icelos. Those figures are associated mainly with dreams, especially in later Greek and Roman traditions, whereas Hypnos represents sleep itself. His name survives in modern words such as “hypnosis” and “hypnotic.”