It is likely that the smoke was thought to have protective powers.

All felt security in evil dealings, because of the protective power that the crooked society gave them.

These guardians are considered as having protective and healing powers.

I see the legends didn't lie when they spoke of the blade's protective powers.

This one was open to the elements when not utilizing the protective power of its invisible energy screen.

From these rituals, it is clear that the fire was seen as having protective powers.

Not while shells burst on the outskirts of the fog itself, but only when one landed, did they know the protective power was off.

His farewell present was a sacred mace + which had special protective powers.

Probably they didn't believe the screen had enough protective power in its normal state, and that's why they were beefing it up.

There is also no protective power which could bring him down.