At the southeastern corner, Shang saw a Mid Archmage enter.
An instant later, they exploded into a shower of gore.
Then, an Early Archmage entered and exploded.
The barrier only restricted more powerful people from entering. If they so chose to, weaker Mages could also fight the defender of the flag.
The Judgment Palace was sending in one fighter after the other, which immediately committed suicide.
Of course, there was a certain limitation to the rules. Only people within one Realm of difference were allowed to fight. That rule was to make sure that no weak and innocent people were accidentally killed since very weak people didn't necessarily know what was going on.
This meant that no one below the Early Archmage Realm was allowed to trigger the barrier and "fight" Shang.
So, every single person that entered and exploded was at least an Early Archmage.