Distortion?

Xukong was currently floating around in the mysterious ring and a small distance away from him was the ethereal altar. During the time Xukong had spent in the ring he had tried to approach the altar many times,  but he never could unless Lin Mu himself was present here.

Every time he would get close to the ethereal altar a mysterious barrier would appear and would block him. This prevented him from going any further and the closest he could reach was within a hundred meters of the altar. 

The barrier that blocked Xukong was an enigma to him. He could not recognize any of the runes that were present on it and neither could he recognize the script. It wasn't written in the Dao scrips and neither was it written in any of the other common scripts that numbered in the millions.