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 in popular culture elements tantalum and niobium are always found together in nature, and have been named after the King Tantalus and his daughter Niobe. The element promethium also draws its name from Greek mythology, as does titanium, which was named after the titans who in mythology were locked away far underground, which reflected the difficulty of extracting titanium from ore. The U.S. Apollo Space Program to take astronauts to the moon, was named after Apollo, based the god's ability as an archer to hit his target and being the god of light and knowledge. Oceanographer Jacques-Yves Cousteau named his research ship, a