This skill is only found from one boss in Nightfall. Amiresh the Pious is located in the Alkali Pan, but you can only reach him with the use of Wurms. Even worse, the area the boss is in can't be exited, you are forced to fight him in the Wurms. This makes it much easier, as your damage is better, and your survival is easier. However, this brings up what I always wondered about. Did Anet once consider what the skill does when they set the boss where they did?
Divert Hexes is a powerful hex removal elite, yet there is no possible way to hex this boss or his group while in the Wurms. Why not provide that boss with an elite that would see some action? Word of Healing, Scribe's Insight, Light of Deliverance, etc. all could be used well by a boss not dealing with hexes. Even Signet of Removal would work, as you at least have options to supply conditions while in Wurms.
Are there other bosses I overlooked that have similar issues? I'm not aware of any, but I didn't do a study of them. I just liked using Divert Hexes, and wondered why a powerful skill like this doesn't ever get used by the boss who has it. I'm not even aware of any monsters other than the boss that uses this elite. The undead Monks use Signet of Judgement, the Margonites use Spell Breaker, Word of Madness uses Defenders Zeal, and all other monsters use other elites as well. So why does Divert get tossed aside, and never used by monsters?
Just thought this would be an interesting discussion
