Second Titan War

The Second Olympian War, also known as the Second Titan War or simply the Titan War, was a war in which the Titan Kronos attempted to take his revenge on the Olympians for defeating him and sealing him in Tartarus. He was opposed by the Olympians and the demigods of Camp Half-Blood, including Perseus Jackson. The plot of the series revolves around Kronos' plans, who hopes to rule the world once again by defeating the gods in the war. There are four major battles mentioned: the Attack of Camp Half-Blood, the Siege of Poseidon's Palace, and contemporaneous battles of Mount Othrys and Manhattan. It lasted approximately four years after Luke Castellan stole the Master Bolt and the Helm of Darkness.

The Master Bolt and the Helm of Darkness
Luke Castellan, a son of Hermes, was contacted in his sleep by Kronos, lord of the Titans. The nature of this encounter is unknown, but he was convinced to join Kronos' cause out of a desire for revenge. He was assigned to steal the Master Bolt, Zeus' primary weapon, and the Helm of Darkness, Hades' godly weapon, in order to start a war between the gods.

On a winter camp field trip to Olympus, he made his move. While the other campers and counselors were asleep, he entered the throne room and stole the Master Bolt and the Helm of Darkness with little effort, as the Olympians would never believe that anyone was capable of doing so. They later discovered the theft and went to search for the thief. Ares, son of Zeus, was the one that found Castellan and disarmed him before taking the two items away from him. However, Kronos spoke to Castellan and told him what to say, which convinced Ares not to return the stolen items as it would lead to a huge war between the brothers.

Ares was intrigued and delighted at the idea of a god-war, and spared Castellan, but took the bolt and the Helm with him. Ares later gave Jackson the Master Bolt in disguise, thinking that Jackson would unknowingly bring the bolt to Hades and Jackson would die in the Underworld. This would cause Zeus and Poseidon to become angry at Hades, and Hades would be mad at them because he would think one of them stole his Helm of Darkness. When Jackson didn't die in the Underworld, Ares tried to kill Jackson himself, but failed and was forced to flee. Jackson sent the Helm of Darkness back to Hades by giving it to the Furies, then returned to Olympus to give Zeus his Master Bolt. Jackson explains that Ares was being used and someone else was making plans behind the scenes. Jackson later learns that Castellan was the one that stole the sacred items under orders from Kronos, his new master. Castellan tries to kill Jackson with a Pit Scorpion before leaving the camp. Jackson is healed in time, but the entire camp now knows of Castellan's betrayal.

The Golden Fleece
After his defection, Castellan took control of a monster cruise ship called the Princess Andromeda, which served as his base of operations. In order to render Camp Half-Blood defenseless and eliminate a major ally of the Olympians, he poisoned Thalia's tree with the help of a spy in the camp's ranks, then he tried to steal the Golden Fleece to use in healing Kronos, planning to later "allow" Jackson and Annabeth Chase to take it and heal Thalia's tree so Thalia Grace, daughter of Zeus, could be purged from it. He did this because he wished to use Grace to fulfill the prophecy made about a half-blood child of one of the Big Three.

Castellan also ensured that Chiron, trainer of heroes, took the fall for the poisoning of the tree, causing him to be discharged from the camp and to be replaced by Tantalus. This worked effectively because Chiron was a child of Kronos and Castellan knew the Olympians would suspect him over anyone else.

At first, Clarisse La Rue was sent to find the Golden Fleece. Meanwhile, Jackson, along with group of allies consisting of Chase and Jackson's half-brother, the Cyclops Tyson, went to save Grover Underwood from the Cyclops Polyphemus.

Hermes persuaded Jackson to go on the quest and guided Chase and Tyson to go as well. Hermes told Jackson to go onto the Princess Andromeda, hoping that he would meet up with Castellan and convince him to stop his assault on the gods. Jackson and his allies landed aboard the Princess Andromeda, not knowing of it's true nature, and were captured.

During this time, Castellan told the two of his plans to use the Golden Fleece to complete Kronos' resurrection and attempted to recruit Jackson and Chase to his cause (not willing to recruit Tyson as he reminded him of the Cyclops that captured him and Grace years ago). When the two refused, Castellan ordered his bodyguards to feed the trio to a drakon. Jackson and the gang escaped through a lifeboat propelled by a wind canister given to him by Hermes.

Castellan later intercepted Jackson and his friends while they were looking for a boat that they could use to get back to camp. While he was asking Jackson for the Fleece in front of a fountain (his army of monsters watching), Jackson used the fountain to send an Iris message, tricking Castellan into revealing the fact that Chiron was framed for the poisoning, resulting in Chiron being rehired. Enraged, he ordered Jackson and his friends to be killed. Jackson convinced Castellan to duel him, a moment both had been waiting for a long time. Castellan effortlessly defeated Jackson, but was prevented from killing the latter when he was knocked into the pool by a boxing glove glued to an arrow. The arrow was shot by Chiron and his family of centaurs who had just then arrived and proceeded to save them. After Jackson escaped, Castellan's spite and hatred for the son of Poseidon only increases.

Grace was resurrected from her tree after the Golden Fleece worked its magic too well, giving Kronos another chance to manipulate the Great Prophecy.

Search for the Ophiotaurus
After Grace's resurrection, Kronos' second in command, Atlas, devised a plan to capture the Ophiotaurus, which would grant the power to destroy Olympus to whomever killed it and burned its entrails. He remembered the Great Prophecy and chose Grace to be its killer. The attack on Olympus was supposed to happen after Grace sacrificed the Ophiotaurus.

Castellan was assigned to aid Atlas with this. However, Grace and Castellan were childhood friends and romantically attracted to each other, bringing Castellan hesitation to carry this mission out. Knowing this, Kronos told Castellan that if he didn't succeed in this mission, he would be chosen to be Kronos's host and therefore suffer a fate worse than death.

Some time before his mission in the Labyrinth, Castellan journeyed down to the Underworld to perfect his design as Kronos's host. Making his way to the River Styx without being spotted, Castellan bathed in the waters, granting him the Curse of Achilles, which made him immune to injury, except in one particular spot.

The first time this (Castellan bathing in the River Styx) was hinted was in a nightmare of Jackson's, where he carried the sky in a plan to trick Chase into holding it after she was captured, which of course succeeded. He and Atlas later used this to their advantage by forcing a captive Artemis hold the sky in her place, and Castellan was happy that Chase survived. He also convinced Atlas to keep Chase alive until Winter Solstice. It is a certainty that he bathed in the River Styx before this, as he would not have been able to hold the sky otherwise.

Castellan was later seen with Atlas when he summoned Skeleton Warriors to hunt down Jackson.

When Jackson, Grace and Zoë Nightshade, the lieutenent of the  Hunters of Artemis at the time, arrived at Mount Othrys, the regrowing fortress of the Titans, where Artemis and Chase are held captive. Refusing to have to kill Grace, Castellan attempted to sway her into joining their side. Grace refused and the two engage in a duel. Their ferocity and power demonstrated was incredible, but Grace ultimately won the duel, disarming Castellan and cornering him against the edge of a cliff (she claimed that she was always able to beat Castellan in a duel). Castellan continued to goad Grace, Chase begging her to spare the traitor. As Grace and Chase argued over his fate, Castellan attempted to use the opportunity to disarm Grace, but she kicked him off the cliff, which causes her much guilt later on.

Although his corpse was seen by both an approaching army of monsters and Jackson, it was later revealed that Castellan was still alive. This is because Castellan had dived into the River Styx, which made him almost invincible.

After her battle with Castellan, Grace pledged herself to Artemis (though she had previously scorned the offer), in order to stop the prophecy from coming true through her. It is possible she was also thinking of Castellan when she made this decision.

Mission in the Labyrinth
Due to his failure to kill the Ophiotaurus, Kronos kept true to his word, assigning Castellan as his next host. However, before Kronos would take Luke's body, the latter would aid him in planning an invasion of Camp Half-Blood using the Labyrinth, which had an entrance hidden between two rocks which Jackson and Chase found while playing a game at Camp Half-Blood.

In order to pass the gladiatorial arena in the Labyrinth he had to assign some of his monsters to fight to the death. When Jackson saw him, he had to show the giant Antaeus one more match. Then a captive Jackson arrives along with Chase and Rachel Dare. As a result, the owner of the gladiatorial matches had Jackson face off against three opponents, the first is easily defeated, Ethan Nakamura, who was defeated with some effort and the giant himself, whom was defeated by Jackson. As a result, Castellan sent his monsters after them, but they escape with the help of Daedalus's hellhound, Mrs. O'Leary.

During this time, Oceanus began to make war with Poseidon, incapacitating him when the other gods fought Typhon until the final battles at Manhattan and San Francisco.

Kronos's Return
When the time had come, Castellan was somehow put into a trance. Two telekhines, along with Nakamura, perform a ritual to resurrect him. Jackson arrived to stop the ritual, but it is too late. When Nakamura pledges allegiance to Kronos, the Titan Lord rose inside Castellan's body and was given the reforged weapon, Backbiter, his scythe with which he had used to kill his father Ouranos. However, Jackson was rescued by his comrades, notably Dare, who threw a blue plastic hair brush at Kronos, allowing Jackson to get away. Nico di Angelo sealed their survival by summoning a boulder over the fortress where the ritual was performed. This also saved Camp Half-Blood by preventing Kronos from taking part in the Battle of the Labyrinth.

A Hero's Death
During the Battle of Manhattan, Castellan was completely controlled by Kronos. During this time, Jackson learned that when Kronos achieved full power inside of Castellan's body, he would burn through Castellan's body and attain his true immortal form, which would mean any mortal that was in the vicinity would be destroyed, and empower the other Titans, giving them ultimate power.

Kronos made his way to the throne room of the gods with Nakamura, destroying the city of Mount Olympus as he did so. Meanwhile Jackson, Chase, Underwood, and Grace followed closely after. Grace's legs were trapped under falling debris, saving Chase from Hera's curse and the others continued on. Kronos battled them in the throne room when they arrived, but Chase was able to catch Castellan's attention, reawakening him, if only partially.

Nakamura betrayed Kronos and attacked him, unsuccessfully of course, as his sword shattered against Castellan's invulnerable body. Several shards lashed back at Nakamura and impaled him, and he staggered to the ground. Kronos, now having an internal struggle with Castellan, opened a fissure in the floor beneath Nakamura, and he tumbled to his end. Kronos continued to batter the trio, getting closer to his ultimate transformation to his original self.

But Chase managed to coax Castellan back to his own mind. Castellan let Jackson knock Backbiter into the hearth, where it was destroyed by the goddess Hestia, leaving Castellan defenseless. A beaten Chase gave Jackson her knife, as they both realized that Castellan was the true hero of the prophecy. Jackson gave the knife to Castellan, who stabbed himself in his mortal point, his left shoulder.

Around this same time, Roman centurion Jason Grace, son of Jupiter, led Camp Jupiter to attack Mount Othrys. As the Romans fought Scythian dracanae, Grace toppled the black throne of Saturn and destroyed the Titan Krios singlehandedly. This possibly aided Castellan gain control over his body and helped Camp Half-Blood defeat the Titans in Manhattan.

After the battle, Jackson, Chase, and Underwood looked away from the following explosion and Kronos's fading screams. Castellan was left lying on the floor, dying. Chase said that he would go to Elysium and Luke replied, "Think … rebirth. Try for three times. Isles of the Blest." Chase replied that he always pushed himself too hard. Then Castellan asked Chase if she loved him, and Chase replied that she thought she did but truly thought of him as a brother. Then Castellan pleaded to Jackson to not let this happen again. With that Castellan died just before the gods arrived, after defeating Typhon, thanks to Poseidon returning defeating Typhon. In the end he was taken away by the Fates, after being blessed by Hermes, and remembered and honored as a hero by not only Jackson, Chase, and Underwood, but by all.

Aftermath

 * Jackson was given the gift of becoming a god, but declined due to his love for his friends and Chase, who he was finally able to tell his feelings to. Instead, he requested that the gods claim their children by the age of thirteen and for Camp Half-Blood to construct cabins for the minor gods and Hades, and that the peaceful Titans should be released. He was thinking of Calypso in particular, a kind, beautiful Titan that was confined because of her father Atlas, but all the other peaceful Titans were also released.
 * Underwood was promoted to become a member of the Council of Cloven Elders by Dionysus, and was deemed a Lord of the Wild. From this, he gained the respect of many nature spirits and the satyrs. He also was coordinating demigod searches with more demigod children being claimed all over the world thanks to Jackson's request to the gods.
 * Tyson was made a General of the Cyclopes for his bravery in leading the charge against Typhon. He was also had the choice of any weapon he wanted which was a new club to replace the one that was broken in the battle. Zeus said that they would search for the finest club that could be found. (Tyson refers to his club as a stick.)
 * Chase, as a reward from her mother Athena, was given the opportunity to rebuild Olympus in whatever way she wants as its new architect. Ares, Aphrodite, and Apollo almost immediately asked for numerous statues of themselves everywhere. She was also in charge of the designs for the new cabins at camp.
 * Dare went to Camp Half-Blood and takes in the spirit of the Oracle now that the curse had been lifted as Hades's children have their own cabin and are accepted by the other gods. She immediately revealed the next Great Prophecy, which the Romans had already remembered as the Prophecy of Seven. This will be fulfilled during the Second Giant War.
 * After his sucess at the Battle of Mount Othrys, Grace was raised on a shield by the entire Twelfth Legion and promoted to the rank of praetor. He served as praetor for only two months before he and Jackson were exchanged in preparation for the upcoming war with the Gigantes.

The Lightning Thief
In the first book, Jackson, Chase, and Underwood embarked on a quest to save Jackson's mother, who was currently held hostage by Hades, and to find the Master Bolt and later, the Helm of Darkness and return them by the Solstice to prevent a war amongst the gods. The prophecy is:

''You shall go west and face the god who has turned

You shall find what was stolen and see it safely returned

You shall be betrayed by one who calls you a friend

And fail to save what matters most in the end.''

The Sea of Monsters
In book two, Jackson, Chase, and Tyson sneak out of camp to help La Rue find the Golden Fleece and bring it to Camp Half-Blood to save Thalia's Tree, which has been poisoned by Castellan. They also go to save Underwood, who was caught by Polyphemus, the Cyclops. They are given this prophecy:

You shall sail the iron ship with warriors of bone

You shall find what you seek and make it your own

But despair for your life entombed within stone

And fail without friends, to fly home alone.

The Titan's Curse
The third addition to the series sees Nightshade, Grace, Bianca di Angelo, Underwood, and Phoebe, later replaced by Jackson embark together to save Chase and Artemis, whom are both being held against their will. The Oracle of Delphi gives them this prophecy:

Five shall go west to the Goddess in chains

One shall be lost in the land without rain

The Bane of Olympus shows the trail

Campers and Hunters combined prevail

The Titan's curse must one withstand

And one shall perish by parent's hand

The Battle of the Labyrinth
In the fourth adventure, Underwood, Jackson, Chase, and Tyson go into the Labyrinth to find Daedalus and Pan. The prophecy is as follows:

You shall delve in the darkness of the endless maze,

''The dead, the traitor, and the lost one raise. ''

You shall rise or fall by the ghost king's hand, 

''The child of Athena's final stand. ''

Destroy with a hero's final breath, 

And lose a love to worse than death.

The Last Olympian
In the last of the first series, the Great Prophecy is finally revealed to Jackson:

<p style="text-align:center;">A half-blood of the eldest Gods

<p style="text-align:center;">Shall reach sixteen against all odds

<p style="text-align:center;">And see the world in endless sleep

<p style="text-align:center;">The hero's soul cursed blade shall reap

<p style="text-align:center;">A single choice shall end his days

<p style="text-align:center;">Olympus to preserve or raze

At the end of The Last Olympian, the Prophecy of Seven is revealed:

<p style="text-align:center;">Seven half-bloods shall answer the call

<p style="text-align:center;">To storm or fire the world must fall

<p style="text-align:center;">An oath to keep with the final breath

<p style="text-align:center;">And foes bear arms to the Doors of Death