Shadow Invasion

Zant's Invasion of Hyrule is the fanon name of a large-scale invasion launched against the land of Hyrule by Zant, the usurper King of Twilight featured in Twilight Princess.

Ganondorf's Execution
Following his capture and imprisonment for his crimes following the end of Ocarina of Time, the Gerudo King of Thieves and King of Evil, Ganondorf, was sentenced to death by impalement in the infamous Arbiter's Grounds. The Sage of Water brandished the Sword of the Sages, impaling Ganondorf through his chest and leaving him with a glowing wound. However, the Triforce of Power activated within Ganondorf at that moment, renewing both his malice and his strength and preventing death from overtaking him. The evil Gerudo soon broke free of his heavy manacles and used his new-found power to kill the Sage of Water before ripping the blade from his torso and turning it on its owners. Left with no choice to prevent the Dark Lord from killing them all and escaping, the Sages activated the Mirror of Twilight, opening the gateway between Hyrule and the Twilight Realm, and sent Ganondorf through it.

The Rise of Zant
Some years later, the Twilight Realm entered a period of political instability when an evil Twili named Zant usurped the throne from the true heir, Princess Midna. Zant had been a servant of the Royal Family of the Twilight Realm, and was embittered that he was not chosen as successor. With the ascension of Midna to the title of Twilight Princess, Zant became emotionally unstable and severely depressed. It was in this state that he was approached by the spirit of Ganondorf, who posed as a god and offered an exchange: he would give Zant the power to take the throne by force, and once he was secure as the ruler of the Twilight Realm, Zant would release Ganondorf back into Hyrule.

Zant transformed the Twili into Shadow Beasts and attacked the Palace of Twilight, where he overthrew Midna by force and transformed her into an impish creature before she escaped Zant's coup. He then sealed away the Sols, the source of light in the Twilight Realm, within the Palace of Twilight, leaving the land in darkness.

The Invasion of Twilight
Zant opened the gateway between the two worlds and used his sorcerous powers to shroud the areas he conquered in twilight. Zant first targeted three of the four Light Spirits that had been responsible for locking the Dark Interlopers away in the Twilight Realm long ago. He sent his Shadow Beasts to steal their light and divide it up amongst a multitude of twilit insects that would scatter around the provinces. The Twili army conquered province after province with ease until they reached Hyrule Castle.

The Twili army eventually even reached the gates of the fortified Hyrule Castle Town itself, invading the city and forcing the surrender of its inhabitants. He forced open the gates of the castle and marched into the throne room in defiance of the brave soldiers who ineffectually tried to stop him. He reached Princess Zelda herself, whom he presented with an ultimatum: to surrender or die.

Zelda, not wishing to risk the lives of her people against seemingly impossible odds, dropped her rapier sword as a sign of surrender. Twilight surged from Hyrule Castle and covered the land like a shroud, causing much of the Hylian populace to be reduced to spirit form, unaware of what had happened to them. With this, the land was under Zant and his master Ganondorf's control.