Shen Lian stood on the rooftop, but he was not only on the rooftop. He was one with the temple, the far away sunset, and everything in the world.
He zoned out of being "me", and the world stood out in contrast. Yanxu seemed out of place.
This was not something that could be achieved with just any supernatural power or Dao technique; it was "force".
Despite the extremely advanced state that Shen Lian was at, he felt uncomfortable still. That was when he finally realized what a scary character Yanxu was, and how his capabilities were beyond his imagination.
This force that blended in amidst the heaven and earth did not affect Yanxu at all, it was as though he did not exist in the heaven and earth, and hence there was no need to be extracted from it.