Theisio saw his knights giving up their lives and knew that it was due to his insufficient level. If he was able to reach level 15, he would be able to break through the space's barrier and communicate with his god.
Because the nature of sacrifices enabled the Lord of Glory to break through such obstacles to obtain the life force of the knights directly, which were then fed back to the knights in the form of divine power. As such, there would be no such thing as sealed space.
Only sacrifices were not restricted in that space, which meant the limit was imposed to rules below level 15. When someone reached level 15, they would be able to open up a portal through sheer force.
If it were inside the energy barrier, not even level 18 gods would be able to transfer power through planes.
The inner part of the cemetery only suppressed powers level 15, while the outer part suppressed powers at level 12.
