I darkwraith every area in the game at levels 40 up to 120+. In my hundreds of hours doing this, I see all types of spells,weapons, shield choices used.
I was in Sens the other day on my level 50 guy catching hosts who were sandbagging the level in my opinion.
A guy jets to summon Tarkus as I expected him to. No matter, I will run past Tarkus on the bridge and kick the host off of the bridge...
As I pass Tarkus, this is when I notice a purple ring around my toon.
Host spams great fire balls/chaos at me while Tarkus is closing in from behind me.
After dodging a few, I panic and switch to my own chaos balls...uh oh..
The flame does nothing, I am stuck in a useless animation and boom..one shotted by Iron Tarkus.
This was the first time I have run into Vow of Silence and since then I have been working on a guy that uses this buff in addition to GMB/flash sweat when applicable.
Just wanted to share a story where I WASN'T the one who came out on top.