- "You don't have to look so sad! We actually find it to be quite livable! I mean, is perpetual twilight really all that bad?"
- — Midna
Twilight is matter originating from the Twilight Realm that plagues Hyrule during The Legend of Zelda: Twilight Princess. The self-proclaimed Twilight King, Zant, was granted power over twilight by Ganondorf in exchange for his body being used as Ganondorf's spirit's host. Ganondorf's plan involved mixing light and shadow to create darkness, and thus Twilight covers the land, reducing Hylians and other inhabitants of the Light to spirits and giving shadow power to various enemies and transforming the land into the Dark World. Eventually, Link restores power to the Light Spirits of Hyrule, cleansing the land. The twilight disappears completely after the death of Zant.
When a normal person enters the Dark World, he or she, if not a twili or another inhabitant of the Twilight Realm, is usually morphed into a spirit. However, those who possess a piece of the Triforce or other type of sacred power are normally immune to it's effect. In Link's case, he became a "divine beast" for some unexplained reason.
Midna makes it clear that in order to enter a place where twilight lurks, one must be a creature of the twilight or have a twilight creature take them inside it. Midna also states that not many people can leave the Dark World easily. When a person is transformed by twilight, according to the Light Spirit Ordona, it is usually not possible to regain their true form unless they dispel the Dark World. However, awakening the Light Spirit in that region will accomplish the task.
Twilight creatures use the aid of portals to transport in and out of the twilight. Midna and Ganondorf to a certain extent, have the ability to change into twilight and use it to warp. In Midna's case, she can also turn others into Twilight. Using twilight, Ganondorf took over Princess Zelda's body.
Towards the beginning of the game, twilight covers most of Hyrule - transforming it into the Dark World, but has not yet spread to Ordona Province and the surrounding area. As the Hero Chosen by the Gods, Link undergoes the awakening of his "divine beast" form (a wolf) which he is forced to maintain whenever in a twilit area until he gains the Master Sword. Over the course of the game, Link clears Hyrule of twilight in large chunks by awakening Light Spirits.
Twilit is a term used to refer to bosses, people, and enemies powered or altered by the effects of Twilight. Twilit beings are created by Zant, corrupted by pieces of the Fused Shadow or Mirror of Twilight, or are transformed by Twilight itself when it encroached on an area. Examples of Twilit beings include the Twilit Arachnid, Twilit Bloat, and Twilit Bulblin.
Patches of Twilight (known as Twilight Realm) cover Keeps on the Twilight Field stage in the Land of Twilight story scenario. These Twilight Realm Keeps have special Keep Bosses, that are Twilit versions of Darknuts and Aeralfos, called Dark Darknuts and Dark Aeralfos. Defeating the Keep Boss in a Twilight Realm Keep, will cause the veil of Twilight to disappear. Due to her Twili origins, Midna draws strength from these patches of Twilight and make defeating her during the scenario harder (however it is possible to defeat her even when she is receiving power from them). Removing all the Twilight Realm Keeps returns Midna to normal.
Unlike its depiction in Twilight Princess, Twilight does not turn Light World beings into spirits, nor does transform Link into Wolf Link. In fact, besides Dark Darknuts and Dark Aeralfos, it has no effect on monsters either. These changes to the way Twilight works, remain unexplained and its effects from Twilight Princess were likely ignored/changed so as to not to effect gameplay in Hyrule Warriors. One possible explanation for this is that Cia's use of the Triforce to warp time and space, altered how the Twilight effects beings native to the Light World.
Midna, Twili Midna, and Zant all use Twilight magic (such as Twilight Portals and Twilight energy) as part of their movesets. The Palace of Twilight also appears as a stage.
Twilight also appears as part of the Twilight Princess DLC Adventure Mode map. Areas of the Twilight map covered by Twilight add special Twilight Rules to scenarios. Twilight can be dispelled with a Tears of Light Item Card.
In Linkle's Tale: Her True Self story scenario, Princess Zelda senses a dark magic that threatens to drive the light from Hyrule. It is later revealed that this magic is actually out of control Dark Twilight Magic. Dark Twilight Magic is depicted as an evil form of Twilight Magic that is capable of producing Dark manifestations of Midna and Zant in the form of shadowy doppelgängers known as Dark Twili Midna and Dark Zant. It also able to produce Dark Aeralfos and Dark Darknuts, however it is unclear if they are manifestations or normal enemies under the effects of Twilight. Princess Zelda does her best to halt the flow of dark twilight magic, but is overwhelmed by Dark Zant and Dark Twili Midna. Fortunately, Midna finds a Shadow Crystal that restores her to her true Twili form and together with Linkle, she manages to rescue Princess Zelda, defeating Dark Zant and Dark Twili Midna. As the Ruler of Twilight, Midna tells Zelda that she will deal with the Dark Twilight Magic. However even Twili Midna's power proves not enough to halt the flow of dark twilight magic and is forced to shatter the Shadow Crystal to release enough energy to contain it, though the loss of the crystal causes Midna to revert to her cursed imp form.
The original concept of twilight was vastly different from the twilight that made it in the final version of Twilight Princess. Instead of being yellow and golden, the twilight was originally a colorless realm of black and white. Only the characters themselves had any color. This was changed for unknown reasons when the game was delayed in the summer of 2005.