The Heroes of Olympus is a pentalogy of fantasy-adventure novels
written by American author Rick Riordan. The novels detail a conflict
between Greek demigods, Roman demigods, and Gaea (Roman name Terra)
also known as Mother Earth. In the fourth book of the series, there is
also a semi-large fight against Tartarus, which, in Greek mythology,
was the darkest and deepest point of the underworld. The series is a
sequel to Percy Jackson & the Olympians, which detailed the life of
modern-day Greek demigods. The sequel to this series, and the 3rd
series in the trilogy is The Trials of Apollo. Riordan introduces
Roman mythology in his sequel series as well as several new
characters. The first book of the series, The Lost Hero, was published
on October 12, 2010. The final entry in the series, The Blood of
Olympus, was published on October 7, 2014.The Heroes of Olympus is
centered around a prophecy, introduced in The Last Olympian, that
predicted seven demigods would unite to protect the world from an
awakening new enemy, Gaia. Demigods from both the Greek camp, Camp
Half-Blood, and a newfound Roman camp, Camp Jupiter, unite to save the
world from being destroyed by the terryifying Earth Goddess, Gaia. The
prophecy reads:The Heroes of Olympus is centered around a prophecy,
introduced in The Last Olympian, that predicted seven demigods would
unite to protect the world from an awakening new enemy, Gaia. Demigods
from both the Greek camp, Camp Half-Blood, and a newfound Roman camp,
Camp Jupiter, unite to save the world from being destroyed by the
terryifying Earth Goddess, Gaia. The prophecy reads:Seven
demigodsâ€"Annabeth Chase, Leo Valdez, Percy Jackson and Piper McLean
from Camp Half-Blood, with Jason Grace, Frank Zhang, and Hazel
Levesque from Camp Jupiterâ€"join forces. A storm or a fire will
destroy the world (Which means either Leo or Jason will have a
terrible fate in store). The last line details how 2 demigods, a
giant, and a titan will free the Doors of Death.Some other important
characters are Nico di Angelo, Son of Hades, Reyna Avila
Ramirez-Arellano, Praetor of Camp Jupiter and daughter of Bellona, and
Gleeson Hedge, a satyr. In the books, they are the main people trying
to bring peace between the Greeks and the Romans while the main 7
characters are fighting the main battle. Without their unity, it would
be impossible to defeat Gaia and save the world. The Heroes of Olympus Top Movies & Young Movies