Henry had commanded the enforcers to kill the soldiers.
In order to keep the secrecy of this whole situation—the soldiers transporting the other part to complete the Primordial Permit needed to be killed. That way, the information regarding what Rex was going to do would not be leaked out.
Considering where they were, this wasn't a really surprising move.
Rex understood that if any person from High Lord Ursa's side heard that he was about to go somewhere using the Primordial Permit to prepare—for the Purgation Duel—there would be people sent to intercept him.
The rules only stated no fighting until the Purgation Duel, so Rex wouldn't be attacked.
But he would be blocked from going to any realm, and that would be a really big problem.
As for the enforcers, Rex believed that they had been thoroughly vetted, so he could trust them.
It was probably the reason why these enforcers aren't particularly strong, but they were all of old age.
