Mirror of Twilight

The Twilight Mirror is the link (no pun intended) between Hyrule and the Twilight Realm. Made by the gods, the mirror allowed people to travel in between the two interlinked worlds as pleased. Located in the desert, the Twilight Mirror was used to banish and imprison the wrong-doers of the kingdom in twilight, never to be seen again. The inhabitants of twilight, the Twili, are the descendants of dark sorcerors, originally from Hyrule and it seems as if the Twilight Realm and the Mirror was originally made to be a prison rather then a parallel world.

The location of the Mirror of Twilight was well known by most of Hyrule, but many believed it was just a myth. When Link reached its resting ground, the Arbiter's Grounds, he was forced to fight a massive beast, the huge Stallord, in order to reach what remained of the Mirror of Twilight.

It is then revealed by the sages that Zant used his newly aquired powers from Ganon to break the mirror into four shards, but didn't have enough power to shatter it completely (which Midna succeeds in doing at the very end of the game). Link and Midna must then find all of the shards to complete the Mirror of Twilight and transport them to the Palace of Twilight.