Counters are supposed to fire before Block is removed. That makes it easier to handle the deadlier ones (and on the flipside, it keeps Pepperevenge from being too powerful with Attack stacking).
The Curse is particularly nasty. Check to lower the timer is a valid strat, though. Definitely make sure you take Tormentors down in like 1 or 2 shots without him going below 25% (since otherwise the Overseer blocks the attacks).
That boss is one of the toughest there is. He was the reason I made the Forbidden Debug Ball. Ice doesn't slow him down, but finding a chance to use your own Double Time to keep pace with him makes it much easier to react to Coup de Grace. You also definitely want to be blocking when he uses Cement Shoes; fortunately, he can only do it up to 3 times (if Alert level is low, it's just one use). Having a strong shield is very good in general, since he doesn't have any Thunder attacks at all.