Black Barrier

This is the giant wall of twilight that cascades over Hyrule that is only accessible by having someone in the Twilight Realm grab Link and drag him in. When you look at the entrance from afar, it is just a black wall with golden outlining. But when you go close enough, you see these strange markings written on it. "Last time, a shadow beast pulled you through the curtain of twilight... But if you want to go that way this time, you'll need the cooperation of someone FROM the twilight...like me!"

- Midna