Normally speaking, it was difficult for desolate beasts of the five regions to pass the regional walls and move to another region.
These desolate beasts, ancient desolate beast and immemorial desolate beasts could match the respective levels of Gu Immortals, they involved the essence of their regions and as such, it was very difficult for them to leave the domain of the region they had been raised and grown in.
To them, the regional walls were like shackles.
Comparatively, ordinary wild beasts, beast kings or mutated beasts were much more free and could move through regional walls.
This group of ancient cloud beasts that were chasing Fang Yuan, however, were not raised by Southern Border, but originated from white heaven of the immemorial nine heavens.
The regional walls of the five regions had no relationship with them and did not restrict or reject them.