I have to say, Chi Xue and Po Tian were extremely clever. Though they had initially been shocked and worried when they sensed the Lord of the Universe find Ling Tian, they quickly figured out that the Lord of the Universe surely hadn't sought Ling Tian out to stop them from triggering the final tribulation together. After all, if the Lord of the Universe had wanted to stop them, he would have done so long ago—not waited until so many cultivators had gathered here and they had set up numerous formations, including the Myriad Sword Demon Extermination Grand Formation and the Buddha Kingdom World formation. If Chi Xue and the others ignored the Lord of the Universe's warning and continued with their tribulation, the situation could well become something he couldn't control. Based on what Chi Xue, Po Di, and the others knew of him, the Lord of the Universe would never allow that to happen.
After realizing this, Chi Xue and the others breathed a sigh of relief. Even though they had gathered enough power to trigger the final tribulation at any moment, their chances would be much better if they delayed a little longer. There was no lack of cultivators who might come to join them in crossing the tribulation during the time they had left. More importantly, the extra time would let them prepare more thoroughly. Chi Xue and the others could get themselves into peak condition, for instance, and their formations could be made more complete and powerful. All of this would greatly improve their chances of breaking free of the Lord of the Universe's control in the future.
Next, Shi Lin and the others began wondering why the Lord of the Universe had sought out Ling Tian. They knew that he must have something important