So when testing Unyielding Anguish on the Triple Trouble event I found out that:
*It does go trough defiance, so you were able to move husks easily
*It ignores unshakable thus making the Wurm Heads in the second phase very hard to kill and unpredictable.
In my opinion as a World Boss Commander for a Large Community, I find that Unyielding Anguish is a crowd control skill and should not go trough defiance, but remove a stack and same with unshakable