Gigantes

The Gigantes are the children og Gaea and Tartarus. In the Lost Hero, Enceladus mentioned that each Olympian corresponded to a Gigantes.

They are only to be killed with the combine powers of a god and a demigod. (e.g.) Jason Grace asking for Zeus' help, Zeus answers and they defeat Enceladus in The Lost Hero.
 * Enceladus, Pallas – Athena
 * Ephialtes – Apollo
 * Alpus – Dionysus
 * Gration – Artemis
 * Hippolytus – Hermes
 * Mimas – Hephaestus
 * Polybotes – Poseidon
 * Porphyrion - Zeus

In The Lost Hero, they are being risen by their mother, Gaea, wanting the Gigantes to destroy the Olympians for having them defeat Gaea's favorite children, The Titans.

The Gigantes

 * ALKYONEUS


 * PORPHYRION


 * ENKELADOS


 * EPHIALTES


 * EURYTOS


 * KLYTIOS


 * MIMAS


 * PALLAS


 * POLYBOTES


 * HIPPOLYTOS


 * AIGAION


 * AGRIOS


 * THOON