The Greek god Thanatos (死を司る神 タナトス, Shi wo Tsukasadoru Kami Tanatosu, lit. meaning "God who rules over Death") is one of the antagonist deities featured in Saint Seiya. As in Greek mythology, he is the personification of mortality and death, and the twin brother of Hypnos, the Greek god of sleep. In Kurumada's mythos, although he is a subordinate of Hades, the Emperor of the Darkness and ruler of the Underworld, he is a deity with all attributes, and as his lord, he is a sworn enemy of the protector goddess of the Earth, Athena.