I bet you didn't know that there was a first group to enter the maze before Thomas and the others. Well there was and they didn't survive, except one girl. Her name is Dani. Sarcastic, Hilarious, Intelligent, a total smart alec, can get pretty emotional, Easily agitated, she was mentally unstable after the first group was gone. The creators saw that only she survived. They didn't want her to ruin anything, so they made her invisible to help guide the new gladers. She also lived on top of the walls. I know crazy right. Here's the way it happened. (P.S. I don't own any characters except Dani and the first group)