Forging the Trident
Poseidon's elder brother, Hades, who was very skilled in navigating under the earth, led all of his siblings into Tartarus with the intention of freeing their uncles, the Elder Cyclopes (Arges, Brontes, and Steropes) and the Hekatonkheires (Hundred Handed Ones; Cottus, Gyges, and Briares). All six of them were imprisoned in the maximum-security zone of Tartarus, surrounded by huge bronze walls, and a lava moat, guarded fierce demons. Their guardian, Kampê, was the most ferocious and fearsome monster in all of Tartarus, and even Zeus, Poseidon, and Hades initially shuddered with horror when they saw the infernal monster for the first time. However, the gods overcame their fear, and were able to sneak in. Zeus managed to talk to the Cyclopes Brontes, and convinced him to forge powerful weapons for him and his siblings (which would be more powerful than Kronos' Scythe) behind Kampê's back. Together with his brothers, Steropes and Arges, Brontes forged three incredibly powerful weapons, the second of which was the Trident, which was given to Poseidon. The power of the Trident imbued Poseidon with the "might of a hurricane", and he tested his new mighty weapon by striking the earth, which generated a strong earthquake. Shortly thereafter, after Zeus killed Kampê, Poseidon used his Trident to shatter the chains of the Elder Cyclopes and Hekatonkheires, releasing his six uncles.
Shortly thereafter, Poseidon successfully wielded his new mighty weapon during the subsequent 11-year-long war with his father Kronos and the other Titans. The Titans initially had the upper hand in the battles, since they were much more skillful and experienced warriors. However, Poseidon quickly became a formidable warrior in his own right as well, and greatly contributed to the ultimate downfall of Kronos and his titanic followers. During the final battle, Poseidon used his Trident to generate massive earthquakes, and to defeat any Titan who got in his way.
Poseidon's Symbol of Power
After the Titanomachy, the gods (who now called themselves the Olympians) chose Mount Olympus as their official residence, and Zeus as their King, while Poseidon replaced Oceanus as the Lord of the Seas. Hence, while the Trident remained Poseidon's personal weapon in times of need, it also became his Symbol of Power, along with the horse, the bull, and the dolphin. He wielded the Trident on multiple occasions, most notably while fighting sea monsters, or sinking the ships of mortals who had angered him.
Poseidon is seen with his Trident when Percy first meets him in the Throne Room on Mount Olympus.
At the Council of the gods on Winter Solstice, Poseidon sides with his son Percy's judgement. He declares that he wouldn't allow the death of the Ophiotaurus, his Trident appearing in his hand when he was angered.
Although it isn't shown, the telekhines in Mt. Saint Helens claimed to have made Poseidon's trident.
During the Battle of Manhattan, Percy goes up to Olympus and sits on Poseidon's Throne to try and get his father's attention. Poseidon was about to blast whoever it was that dared to sit on his throne with his Trident, but thankfully looked before doing so and didn't blast Percy.
As the terrifying Storm Giant Typhon started his final charge toward Olympus, he stepped into the Hudson River, from whence Poseidon emerged, with an army of Cyclopes, lead by Tyson. As the Cyclopes wrapped him in heavy chains, Poseidon struck Typhon with his Trident, managing to severely wound and weaken the Storm Giant, before creating a channel of water that pulled the defeated Typhon into the pits of Tartarus.
Poseidon joins the Seven Heroes of Olympus in their final battle against the Giants. He and Percy battle and defeat the Giant twins Otis and Ephialtes, with Poseidon spraying them out of the Athenian Parthenon with a high-powered water blast from his Trident after turning it into a water hose.
The Lightning Thief
It is a three pronged spear with thick energy bolts surging through it. To regular mortals, it appears as a surfboard, fishing rod, or ice cream, when he is by the beach due to the Mist. There is an attachment for Poseidon's trident on his throne, where one would expect a fishing pole on a mortal fisherman's chair.
Poseidon's Symbol of Power, the mighty trident was the second weapon created by the Elder Cyclopes, and is rivaled in power only by Hades helm and Zeus' Master Bolt. Through the Trident, Poseidon has a host of awe-striking abilities.
- Hydrokinesis: The foremost ability the Trident had was control over all bodies of water with a potency far surpassing that of Oceanus. Poseidon could easily and instantly change the motion and state of any body of water, from the shallow seas to the deepest depths of the ocean.
- Hydrogenesis: Poseidon could create water from the power of the Trident. As shown in Percy Jackson's Greek Gods, when Poseidon first received the Trident, he tested its power by creating a miniature hurricane in the middle of Tartarus (where there was no natural water). He continued to use this ability, notably using it to create a geyser of salt water in Athens. In The Blood of Olympus, Poseidon is able to transform the trident into a fire hose and blast two giants out of the Parthenon with high-pressure water.
- Atmokinesis: The Trident can create massive storms. In Percy Jackson's Greek Gods, Poseidon is said to have felt "the power of storms" humming through the three pronged spear upon receiving it. During the Titan War, he used it to call up and create massive storms to ransack the Titans, especially in the final battle. Due to his ability summon hurricanes, tornadoes, and tidal waves with the Trident, Poseidon would be dubbed "The Stormbringer."
- Geokinesis: Another ability granted to Poseidon through the Trident was the ability to shake the earth and shatter any object by driving his spear into the ground or said object. Due to this, Poseidon was also hailed as the "Earthshaker." In Percy Jackson's Greek Gods, Poseidon is credited with using the Trident to summon many earthquakes throughout the Titan War.
- Aquatic Transformation: A weapon of immense power with a connection to the sea, Poseidon can utilize his Trident to transform just about any object into a sea related object, or a powerful monster into a docile sea creature. This is best shown in The Last Olympian, when he transforms a sizable sea monster into a goldfish. Also, when Percy sat on Poseidon's throne, Poseidon said, "If I hadn't looked before I blasted, you would be a puddle of sea water."
- Raw Divine Power: One of the three most powerful weapons in existence, the Trident carries immense raw power. In addition to utilizing the Trident's elemental powers, Poseidon can also channel his raw energies of the Trident into a devastating blue energy blast. This is best shown in The Last Olympian, where a Poseidon instantly destroys a giant squid that was "larger than any skyscraper" with an energy blast, dissolving it "like food coloring." Furthermore, Poseidon's trident was the first weapon to significantly injure Typhon (who had barely staggered from a hit from the Master Bolt).
- The trident is the astronomical symbol of the planet Neptune.
- The telekhines in Battle of the Labyrinth claim to be the creators of Poseidon's trident, yet this is contradicted in Percy Jackson's Greek Gods where the creators of the weapon is stated to be the Elder Cyclopes respectively.
- In myth, the most common origin for the trident is it was created by the Elder Cyclopes along with Zeus' Master Bolt and Hades' Helm of Darkness. The books use the less common story of the Telekhines forging it.
- It is able to control all bodies of water.
- It is only rivaled by the Master Bolt and the Helm of Darkness.
- It is the only Symbol of Power of the Big Three that wasn't stolen by Luke.
- As shown in Percy Jackson's Greek Gods, Poseidon used the Trident to smash the chains of the Elder Cyclops and Hekatonkheires, freeing them from Tartarus.
- In Trials of Apollo, Apollo comments on how Poseidon never cleans the moss and algae off his trident.