Who are the parents of the goddess the title of the final novel of the "Percy Jackson & the Olympians" series refers to?
The Last Olympian:  It is the fifth and final novel of the "Percy Jackson & the Olympians" series and serves as the direct sequel to "The Battle of the Labyrinth". The Last Olympian:  The title refers to Hestia, the goddess of the hearth, who refers to herself as such in a conversation with Percy on Mount Olympus. Hestia:  In Greek mythology, she is a daughter of Cronus and Rhea.
Cronus and Rhea