Anemoi four Anemoi and several minor wind gods are involved in the defense of Mount Olympus against Kronos (the Titan Cronus), the first series's chief antagonist. Both the Greek and the Roman forms of the Anemoi appear in Riordan's second series. Boreas is a central character in "The Lost Hero", and his children Khione, Calais, and Zetes continue to have important roles throughout the series. He resides in Montreal, and is described as "sturdily built...with dark purple wings" when in his Greek form, and as "taller and thinner" when Roman. "Notus/Auster appears in "The House of Hades" as a counselor of
Greek mythology Nereids (who inhabited the sea), river gods, Satyrs, and others. In addition, there were the dark powers of the underworld, such as the Erinyes (or Furies), said to pursue those guilty of crimes against blood-relatives. In order to honor the Ancient Greek pantheon, poets composed the Homeric Hymns (a group of thirty-three songs). Gregory Nagy regards "the larger Homeric Hymns as simple preludes (compared with "Theogony"), each of which invokes one god". The gods of Greek mythology are described as having essentially corporeal but ideal bodies. According to Walter Burkert, the defining characteristic of Greek anthropomorphism is that "the Greek