In Greek mythology, Hypnos, also spelled Hypnus, is the personification of sleep. His name is the origin of the word hypnosis. Pausanias wrote that Hypnos was the dearest friend of the Muses. Hypnos is usually the fatherless son of Nyx. His twin brother is Thanatos ("Death"). Both siblings live in the underworld (Hades). Sleepy, wise, kind, thoughtful, caring, gentle, calm. Pale curly medium long hair, blue eyes, two small wings on his head.