Parry on Bosses

Well, there's been some debate raging about the parry mechanics done by mobs. The prevailing theory is that when a mob parries an attack, it speeds up its next auto-attack. This is consistent with what happens with players, and is the simplest explanation for why a mob often appears to have an inconsistent attack speed (lag notwithstanding). Thus, by Occam's Razor, we assume that these random attack speed increases are a result of parry mechanics being the same for mobs as they are for players.

I'll save you the boring details, but I've been digging through several combat logs, examining just what happens to a mob's autoattacks with regards to parries. Examine this sample;

14:44'38.984	Hydrastorm's Melee parried by The Curator
14:44'40.187	The Curator's Melee parried by Everlight	1.219
14:44'40.312	Everlight's Melee parried by The Curator
14:44'41.375	The Curator's Melee parried by Everlight	1.188
14:44'41.968	Everlight's Melee parried by The Curator
14:44'42.593	The Curator's Melee parried by Everlight	1.218
14:44'43.234	Everlight's Melee parried by The Curator
14:44'43.828	The Curator's Melee dodged by Everlight	1.235

The number on the right indicates the swing timer for the mob. Notice how fast his swing speed is here, where parries are involved? Now, in the same fight;

14:44'55.890	The Curator's Melee misses Everlight	2.281
14:44'58.734	The Curator's Melee dodged by Everlight	2.844
14:45'01.140	The Curator's Melee hits Everlight for 1491 (309 blocked)	2.406
14:45'03.578	The Curator's Melee parried by Everlight	2.438
14:45'05.906	The Curator's Melee hits Everlight for 1619 (309 blocked)	2.328

Notice his swing speed when parries are not involved? This behaviour is consistent across the entire fight. I realize that the sample size isn't particularly large, but examination of combat logs tends to show this behaviour is quite consistent. Parries by mobs speed up their autoattack - and it doesn't matter who they parry either.

This sort of effect doesn't matter on a soft boss, but when you're facing down something which already hits really hard, it becomes important. Make your melee DPS fight a boss from the back, and this includes hunter pets, shadowfiends, everything.

So, how do you reduce the chance of a mob parrying you? There's only two ways. One, select a weapon with a slower swinging speed, so you attack less. Two, Weapon Skill. Higher weapon skill reduces your chance to be parried. Expertise also directly reduces your chance to be Parried.

13-Dec-07: Added in info about Expertise.