Giant Army

The Giant Army (also called the Gigantes Army) is an army of giants, mortals, and gods and goddesses, who take part in helping Porphyrion and Gaea destroy Olympus in the second Giant War in The Heroes of Olympus.

History
During World War II, Gaea began to wake from her slumber. While the gods were bust fighting themselves, she sought to destroy them in their weakened state. She began making plans to cause her children, the Gigantes, to rise and once again take down the gods. Her plans began with a demigod daughter of Pluto, Hazel Levesque. Using Hazel's mother, she caused Hazel to move to Alaska and took control of Hazel's mother at night. She then used Hazel's power over the riches of the earth to reform her first son, Alcyoneus. Hazel however sacrificed herself to stop his rise and Gaea went back to sleep. Alcyoneus rose again during the 80's, as Hazel's sacrifice had only delayed his rising. He began recruting monsters to his cause, including Roman Cyclopes and Centaurs. The other Gigantes also began to rise in response to Alcyoneus' awakening.

Meanwhile in the Underworld, Medea used her abilities to see into the future and saw that a son of Hephaestus named Leo Valdez would someday go against Gaea. She informed Gaea of this child and Gaea went to try and break Leo's spirits by killing his mother, Esperanza Valdez.

Shortly after the Second Olympian War, Gaea made her move and her children managed to capture the god of death, Thanatos. With Thanatos no longer able to guard the Doors of Death, Gaea set free Mortals from the Underworld that would help her defeat the gods, who had closed off Olympus in hopes of luring Gaea back to sleep. This also made monster reform much faster, further strengthening her forces.

The Lost Hero
Khione, the goddess of snow that joined forces with Gaea managed to trick Hera into coming to the Wolf House. When Hera arrived, she was trapped by Gaea in a cage of earth and had her power drained so Porphyrion, the king of the Gigantes could rise. Hera used her powers to transfer Jason Grace to meet a group of Greek demigods who would take him to Camp Half-Blood. It was here that Jason was given a quest to rescue Hera and decided to bring his two new friends, Leo Valdez and Piper McLean along for the quest.

The Giant Army kept close tabs on the trio, as the giant Alcyoneus had kidnapped Tristan McLean, Piper's father, in order to make sure she led Leo and Jason into a trap. The snow goddess Khione also kept watch over them and hit them with snow storms during most of their quest. They also ran into monsters that had pledged their allegiance to Gaea, including the werewolf Lycaon, the Gegeines (also known as Earthborn), and Venti. They also learned that evil mortals from mythology were rising from the Underworld, most notably Medea who tried to [[charmspeak Leo and Jason into killing each other, and King Midas who tried to turn them all into gold.

After Piper, Leo, and Jason managed to free Piper's father, the main forced of the Giant Army moved to the Wolf House in order to try and take it back from the Hunters of Artemis, who were being lead by Thalia Grace in defending it. The Lycanthropes and Earthborn attacked the Hunters, who were trying their best to hold them back. However, the monsters would simply reform once destroyed thanks to Gaea's influence. The tide of the battle became even worse once Khione arrived and froze most of the Hunters, including Thalia.

Despite Leo managing to force Khione into a retreat, Porphyrion rose from his slumber and planned on destroying the son of Jupiter, Jason Grace. Leo and Piper however managed to free Hera, who revealed her Divine Form which destroyed all the monsters (except Porphyrion who escaped) in the area. The Giant army as a result was defeated, but managed to accomplish their goal of awakening the king of the giants.

The Son of Neptune
As Percy Jackson made his way to Camp Jupiter, he was attacked by two of the Gorgons, who blame him for Medusa's death. Despite having faded, Gaea managed to bring them back and prevents them from being killed as long as they touch the ground. They also inform Percy during their fights that a large army of monsters is heading south to destroy the camp. Percy however managed to kill them by ripping them apart in the waters of the Tiber River.

Later, Mars reveals that the god Thanatos had been captured so monsters won't die and this will eventually effect demigods and even mortals. Percy, Frank, and Hazel are given a quest to free him, but run into many forces of Gaea on the way to Alaska. They soon learned that Polybotes was leading an army of cyclopes and Centaurs south to face the forces of Camp Jupiter, something the leader of the camp, Reyna, already knew.

When Percy, Hazel, and Frank find the Amazons (as the leader was Reyna's sister), they find that Gaea had called the first queen of the Amazons from the Underworld to cause a civil war between them. Otrera, the original queen, convinced almost half the Amazons to turn away from Queen Hylla and join Gaea in her attack on Camp Jupiter, while Hylla wanted nothing more than to help her sister. For leadership of the Amazons, Otrera challenged Hylla to a fight to the death, but because Otrera couldn't die and would come back if beaten, Hylla had no hope but to simply hold out until Thanatos was free.

Once escaping the home of the Amazons, the trio seek the aid of a blind seer named Phineas, who Gaea had revived to help her see what lies in the future. He is killed and sent to the Underworld after losing a bet with Percy and as a result of the bet, they learned of the location of Thanatos. When arriving at the Hubbard Glacier, they ran into the eldest Gigantes, Alcyoneus. While Frank worked to free Thanatos, Hazel held off Alcyoneus, while Percy was forced to fight an army of Ghouls made up of the old Fifth Cohort. They had pledged their intelligence to Gaea after their death and now existed as mere shades. Eventually, Percy defeated the shades by taking them over a cliff of ice while Frank and Hazel dragged Alcyoneus to Canada with the help of Arion, Hazel's horse. No longer in his own territory, Alcyoneus was easily killed by the combined might of the two demigods.

The trio soon arrived back at Camp Jupiter, where Polybotes was leading the charge. The army of Cyclopes and Centaurs appeared to have the edge until the arrival of the Amazons. At first, they appeared to be helping the Giant Army, but quickly changed course and wiped out most of their forces with the aid of the cohorts. Polybotes as well was defeated with the combined effort of Percy and the god Terminus.

Known Giants

 * Porphyrion - bane of Zeus
 * Enceladus - bane of Athena
 * Polybotes - bane of Poseidon
 * Alcyoneus - bane of Hades
 * Otus
 * Ephialtes

Revived Mortals

 * Medea: a skilled Charmspeaker and sorceress.
 * King Midas: able to turn anything he touches to gold.
 * Lityerses: the son of Midas and a skilled combatant.
 * Phineas: a blind man with the ability to see the future.
 * Otrera: the original queen of the Amazons.

Gods & Goddesses

 * Khione: Goddess of snow. She actively worked to split the gods up from their demigod children by getting Zeus to close Olympus.
 * Aeolus: Predicted, since he sent the storm spirits to fight Jason Grace, Leo Valdez, Piper McLean, and the hunters from saving Hera (tricked by Khione).

Monsters

 * Lycaon
 * Wolves
 * Medea's Sun Dragons
 * Storm Spirits
 * Gegeines
 * Karpoi
 * Cacus
 * Laistrygonian Giants
 * The Gorgons
 * Shades of fallen legionnaires
 * Centaurs
 * Basilisks
 * Lamia
 * Cyclopes