Trident

The trident is one of Ganon's weapons of choice. He is seen wielding one in A Link to the Past, BS The Legend of Zelda, Ancient Stone Tablets, the Oracle series, and Four Swords Adventures.

Four Swords Adventures features a much stronger version, which according to Hyrule Historia has not made an appearance in another game. The trident is held in the Pyramid level, and has an inscription nearby. The inscription would mean that this trident is the exact opposite of the Master Sword. The Master Sword being the ultimate light weapon while the trident is the ultimate dark weapon. Ganon uses the trident to fire a flurry of bolts; when hit, Link is transported to the Dark World. Secondly when Ganon throws it, the trident leaves a trail of blue fire in its path.

Upon his revival in Oracle of Ages or Oracle of Seasons, Ganon wields a trident once again, using it to attack in vicious swipes. He also uses the trident to summon energy balls, as do characters such as Phantom Ganon. However, these attacks cannot be deflected.

A Link to the Past
The trident makes its first appearance in A Link to the Past, where Ganon uses it in the first stage of his boss battle. He will spin it and toss it at Link while sending fire bats after him. After a certain point, Ganon will abandon this tactic and use his secret technique of Darkness in lieu of the trident.

Link's Awakening
Although a trident-wielding Ganon does not appear in this game, the final boss will take Ganon's form and attack Link by throwing a trident at him in a similar fashion to how Ganon attacked in A Link to the Past.

BS The Legend of Zelda and Ancient Stone Tablets
In BS The Legend of Zelda, Ganon fights similarly to how he fought in the original The Legend of Zelda, by turning invisible and shooting fireballs. As such, the trident is merely cosmetic and not actually used in combat. In Ancient Stone Tablets, he uses it just as he does in A Link to the Past.

Ocarina of Time
The trident reappears in Ocarina of Time, this time, wielded by Phantom Ganon. He uses it to summon energy balls and throw them at Link.

Oracle of Ages and Oracle of Seasons
When Ganon is revived in the Oracle of Ages and Oracle of Seasons Linked Games ending, he uses the trident to battle Link. He either attacks with a vicious direct swipe or a flurry of energy balls. Most of these attacks can be dodged using the Roc's Feather or Roc's Cape.

Four Swords Adventures
In this game, Ganondorf found the trident when he broke Gerudo law and entered the Pyramid across the Desert of Doubt. Inside, he found it underneath an inscription that promised its wielder the power to become the King of Darkness. Ganon uses this trident during the final battle, where his attacks include throwing the trident with a trail of blue fire, and shooting a flurry of lightning bolts that send the Links into the Dark World.

Ganon believes that his trident will grant him the power to destroy the Links, threatening to skewer them on it. Princess Zelda recognizes the trident and refers to Ganon as the "ancient demon reborn" because he wields it. A Knight of Hyrule mentions that Ganon used the trident to defeat the Knights and send them into the Dark World.

This game's trident is often referred to as the by fans, in order to differentiate it from the less powerful tridents featured in other games of the series.

A Link to the Past comic
In the A Link to the Past comic, Ganon is seen wielding his trident in the final battle. At first, Ganon's trident easily overpowers Link, and the young hero even gets stuck in between it, rendering him incapable of moving. After Link and Zelda defeat Ganon, Link is seen holding the trident in his hand as the Triforce asks him to make his wish.

Theory
The Trident of may have been crafted by the Interlopers, given that it shares characteristics with the Fused Shadow. Both serve as symbols of authority (one fragment of the Fused Shadow being given to the ruler of the Twili, and the Trident giving its wielder the title of "King of Darkness"), and both have been shown to mutate those who touch them (the Fused Shadow fragments turning a Deku Baba into Diababa, Darbus into Fyrus, and an unknown aquatic creature, possibly a Bombfish, into Morpheel; and the Trident turning Ganondorf into Ganon). However, if the Trident was once an Interloper weapon, it was clearly forgotten, as neither Midna nor Zant mentions or expresses interest in it.

If the Interlopers did indeed craft the Trident, it is also possible that, at least at some point, Ordona watched over it, as the other Light Spirits watched over the fragments of the Fused Shadow. If so, Ordona may have played a role in the construction of the Pyramid, and may thus be linked to the Zuna tribe somehow.

Alternately, this particular Trident may also be a counterpart of Demise's Sword, as both of them are powerful dark weapons of great evil and complete opposites of the Master Sword. Also, as the handle length increases in time, it is plausible that Demise's Sword eventually becomes the Trident of Power, so eventually the evil incarnation of the Demon King will come to wield it to wreak havoc. If it is Demise's Sword, it means that Ghirahim still exists inside the wicked weapon.

Trivia

 * According to the English translation of the Trident inscription in Four Swords Adventures, the Trident houses an "evil spirit". This quote has been re-examined however, and seems to have been mistranslated.
 * Although the trident did not appear in The Legend of Zelda, official art from the time of A Link to the Past shows Ganon wielding it when he fought Link in that game.
 * When Midna attacks with the Fused Shadow, she wields a similar pronged weapon.