Black Barrier

The Curtain of Twilight is the giant wall of Twilight that cascades over Hyrule in Twilight Princess. It is only penetrable by having someone in the Twilight Realm grab Link and drag him in. When seen from afar, the entrance appears to be but a black wall with golden outlining, but when observed at a closer distance, strange markings are seen written on it. Any non-Twili passing into the twilight without the protection of the Master Sword will be affected by its power and transformed, in most cases, into spirits. Though Link, as the chosen hero with the Triforce of Courage, is transformed into a blue-eyed wolf upon passing through it.