
Originally Posted by
aurik
The ability that he spams in the final phase (the aoe damage one) is not meant to be interrupted. It's a burn phase, and the longer the fight has gone on the more brutal it is because of Wracking Pain stacks multiplying the damage. That's basically the reason why you have to interrupt Stay of Exec and Mend Flesh in the first place, the longer the fight lasts the more stacks of Wracking Pain you will have.
Also the open question is why the SP didn't have Silence in the first place. It's an incredibly useful spell.
Finally, a lot of spells that are "immune'd" still cause interrupt. Kinda surprised hunter doesn't have even 1 ability that interrupts an otherwise immune boss; it's probably about the only class that doesn't?