Raid.

The hound beasts stood surrounding the building. They all were moving very quickly around. If one observed carefully then they will find that the movements were not random. Rather they were all digging some spirit stones under the grass around the building. The things they buried under the soil were spirit stones given to them by You Xi Wang. They were all arranging a spirit formation around the building.

It was a level 5 space lock barrier. This formation would lock the space restricting the people inside or outside to escape by using teleportation spells/talismans. Another use was to stop any Nirvana Rebirth expert from interfering. The hounds were natural experts in concealed movement. This is why You Xi Wang tasked them to set-up the arrays and not the humans. The security of the building might alert the people staying inside if they made any mistakes.