Aero had a group of private army.
His private army is also one of the most well supplied and most well armored in the Capital of Vanheim
Most of them were trained hard and they were all elites in their own rights. And most of his private army is the native inhabitants of this world
Some people said this is the Chancellor way of not showing favoritism to other adventurers.
Truth is, Aero trusted the native world inhabitants more than he could trust adventurers.
Because he is also an adventurer he understood very much how useless is trust between one adventurer to another.
And the adventurers might even be spies that could reveal his eccentricities regarding his weakness in the ankle
Why would someone as powerful as Aero need an ankle protector made of some weird metal?
If his private lives are investigated then maybe if Eric looked at it, he could deduce Aero weakness.