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Control Impairing Effects (also known as Crowd Control Effects or CCs) are a recurring concept in ARPGs that refer to any effect that influences, reduces or prevents the actions or mobility of a target. In Diablo III, Crowd Control, whether it affects you or the monsters, is an important mechanic to understand, especially when it comes to Greater Rift pushing. In this article we're going to cover both crowd control effects mechanics on players and crowd control effects on monsters, mainly through the Crowd Control Resistance (CCR) mechanic.
Players & Crowd Controls
Monsters' Crowd Control Abilities
Most normal monsters do not have any form of crowd control, but some can knock you back ~10 yards (Grotesques and Executioners) or stun you for 1.5 seconds (Armaddons and Punishers). All other sources of crowd control that affect you will come from Champions and Rare Elites packs affixes or boss abilities. Here are the crowd control affixes you’ll see in Diablo III:
- Frozen triggers a 2.5 second freeze.
- Jailer is a 2.5 second root.
- Knockback procs a ~30 yards knockback and a 3 second slow.
- Nightmarish triggers a 1 second fear.
- Vortex pulls players within 50 yards to the monster.
- Wormhole teleports players standing still for 1 second in a purple circle to another one.
In addition, some environmental structures can crowd control the player, like the Arreat Hell Bringer that has a Vortex ability (and can be killed), or the Arreat Demon Mines and Halls of Agony Blades that knock you back.
"Crowd Control Lock" Prevention
In order to avoid being "crowd control locked" (being unable to perform any action due to an overwhelming amount of crowd controls in rapid succession), all affixes have an internal cooldown but there are several additional mechanics in place on Champions and Rare Elites packs affixes:
- Vortex triggers a 4 second immunity to itself.
- Knockback triggers a 15 second immunity to itself.
- Nightmarish causes a 6 second immunity to itself.
- Champions packs can only cast Frozen once every 8 seconds.
- Champions packs can only cast Jailer once every 12 seconds.
- Jailer, Nightmarish, Knockback and Vortex are mutually exclusive (Only one of these affixes per pack).
Crowd Control Immunity
Crowd Control Immunity is very valuable to allow full freedom of action to the player. Being crowd controlled can lead to a massive waste of damage and time (like missing a Convention of Elements DPS window, or dying) especially in a Greater Rift push environment. This is why crowd control immunity is added to any build that can afford it.
Crowd Control Immunity makes the players fully resistant to any kind of soft or hard control-impairing effect. Main sources of complete crowd control immunity are:
- Akarat's Champion
- Laws of Justice Bravery
- Iron Skin
- Inner Sanctuary Temple of Protection
- Near Death Experience
- Bone Armor Limited Immunity
- Wrath of the Berserker
- Ignore Pain
- Nerves of Steel
- Demon Hunter
- Smoke Screen
- Witch Doctor
- Spirit Walk
- Spirit Vessel
- Other Sources
- Invigorating Gemstone
These can be used while under any control-impairing effect, breaking it upon cast and granting you immunity for a specified duration. Crowd Control Immunity also prevents you from being interrupted when performing an action with a cast bar such as teleporting to town, identifying items or completing objectives in bounties.
Ignore Pain Mob Rule, Inner Sanctuary Temple of Protection and Laws of Justice Bravery are highly valued in group play as they offer crowd control immunity to the whole party. If you do not have access to any of the aforementioned, consider using Bottomless Potion of the Unfettered. Also Shield Pylon as it grants you complete damage immunity, will also grant you crowd control immunity.
Most movement skills can either break immobilize effects or be used while immobilized even though they don't grant crowd control immunity. For instance, Wizard's Teleport, Demon Hunter's Vault and Necromancer's Blood Rush will break root effects when cast and grant CC immunity during their animation.
On the other hand, Barbarian's Furious Charge and Monk's Dashing Strike can be used while under a root effect, but won't grant an immunity during the animation or break those effects. In addition, channeling Whirlwind makes Barbarians immune to knockback.
Some legendary items grant partial immunities:
- Homing Pads prevents interruptions from damage taken when teleporting to town even though it does not grant crowd control immunity.
- Ice Climbers can be used to give you immunity to immobilize, freeze and even, despite the tooltip, to any slow! This item is mostly used to completely nullify the negative effects of Stone Gauntlets in solo, mainly in Legacy of Dreams setups.
- Krelm's Buff Bracers is sometimes used for its immunity to stuns and knockbacks, but Bracers slot usually has a lot of strong contenders.
Finally, if your build is weak against crowd controls, you can always use the layout to protect yourself. Facing monsters with your back to a wall greatly reduces the effects of some crowd controls such as Nightmarish or Knockback, as your character is not able to move freely due to the environment. Another option is to stack some Crowd Control Reduction on your gear.
Crowd Control Reduction
Players can also protect against crowd control effects by rolling Crowd Control Reduction as a secondary affix. This roll ranges from 20% to 40% and is found on Amulet, Rings and Helmets. Justice Lantern ranges from 35 to 50% and the Barbarian passive Juggernaut gives you 50%. However, this only impacts the duration of the effect.
Multiple sources of Crowd Control Reduction always stack multiplicatively. Thus if you have two sources of control-impairing effect reduction, the formula is:
In practice let's say you have two items with Crowd Control Reduction, one with 30% and the other with 40%:
In this scenario, your character reduces the duration of crowd control effects inflicted on itself by 58%.
Crowd Control Resistance
When monsters are hit by a "Hard" Crowd Control (see below), they build up Crowd Control Resistance (CCR) at a rate of 10% per second the crowd control lasts. On application, the duration of any hard crowd control is reduced by this CCR, which is capped at 95%. Therefore this means the duration of a crowd control can be reduced to the point where it only lasts 5% of its base duration if the monster has built up 95% crowd control resistance.
Note that only subsequent Crowd Controls are impacted by this increased resistance (not the one that caused it). For instance, Mass Confusion will charm the monsters for 12 seconds (assuming they have no resistance from previous crowd control effects) and immediately applies 120% crowd control resistance on the monsters (reducing the duration of any subsequent Crowd Control by 95%) just after the application. This resistance starts to decay only after the Mass Confusion's crowd control effect expires, after 12 seconds.
Mass Confusion in action
Even if Crowd Control Resistance can reduce the duration of Crowd Controls by up to 95%, it does not have any upper cap, eventhough the duration threshold limit (see below) acts as a soft cap. This lack of upper cap becomes obvious with Skull of Resonance + Inspiring Presence which applies a 30 seconds Charm, building up to 300% Crowd Control Resistance on monsters affected, preventing them to be pulled for 47 seconds, until their CCR drops below 65%!
Indeed, Monsters lose the Crowd Control Resistance they have accumulated when they are not under the effect of any Hard Crowd Control effect, at the rate of 5% per second. This explains why players should only use their Crowd Control abilities when needed, to let the monster resistance decay inbetween (see Crowd Control Resistance Management section below).
Stacking several Hard CCs on the same monster does not increase crowd control resistance further. When you apply a crowd control, its duration is calculated in regards to the current crowd control resistance of the monster and only then applies the crowd control resistance but the overlapping time (when the monster is affected by several crowd controls) is not taken into account.
For instance, Horrify fears and roots at the same time; but only triggers CCR for the time the monster spend under this effect. Thus in this case we would witness 30% CCR assuming a 3 second Horrify on a monster without any previously built resistance.
Conversely, Inner Sanctuary Sanctified Ground, which fears for 1 second and knocks back monsters within the Sanctuary on activation, does not actually fear targets in practice. This is because the fear duration is reduced below the threshold by the CCR built on the Knockback. This means Knockbacks follow different rules and apply their flat 40% resistance first and regardless if the monster is already crowd controlled or not.
CC Duration Threshold
Hard Crowd Control effects have a duration threshold limit on the monsters. When a monster has built up enough crowd control resistance to reduce the duration of a hard CC below a certain amount, it will not be affected by this control. This means:
- If the duration of the CC is reduced below 0.65 seconds, it won't affect normal monsters,
Champions and Elite Minions.
- If the duration of the CC is reduced below 0.85 seconds, it won't affect Rare Elites and Bosses at all.
Theoretically this means you could permanently disable monsters assuming you had access to long enough crowd control abilities. All we need is a crowd control whose duration would remain above the threshold when the monster has built up 95% CCR. This means a 13 seconds hard crowd control would still be able to affect monsters. Likewise, a 17 seconds control would be necessary to incapacitate Rare Elites and Bosses for 0.85 seconds.
Knockbacks are treated differently and apply a flat 40% Crowd Control Resistance to the monster, regardless of the effect duration; but only if the monster is actually displaced. Any displacement effect (such as pulling abilities) is treated as a knockback. Moreover, any monster that has built up 65% or more CCR will be immune to any displacement effect.
As a result, any "knockback attempt" when the monster is sitting at 65% CCR or above will not trigger additional CCR because it will not be displaced. Note that an attempted knockback (a displacement effect on a monster with too much resistance or an immune target like a Rift Guardian or a Juggernaut Rare Elite) triggers the damage buff from Strongarm Bracers.
"Continuous" Knockback Effects
Some abilities cause periodic knockback effects for a short period of time. These effects only apply 20% crowd control resistance to monsters instead of the 40% from other displacements; they can also bypass the 65% limit threshold if they already applied a knockback successfully. In practice, this generally means monsters have built up 95% CCR by the end of these effects. There are two cases:
- Black Hole sucks in monsters within 15 yards every 0.25 seconds. This vacuum effect results in consecutive ~5 yards displacement effects.
- Steed Charge Draw and Quarter chains up to 5 monsters and drags them along with the pony.
On a pony ride
Crowd Control Immunities
In the same way players can be immune to crowd control, some monsters have specific crowd control immunities:
- Goblins and Elites with the Juggernaut Affix are immune to any kind of crowd control effect.
- Bosses are immune to any kind of Charm, Fear, Hex, Knockback or Taunt effect.
- The Rift Guardian Vesalius is uniquely immune to Blind.
- Some monsters gain a short immunity while performing specific attacks (such as Winged Assassin & Lacuni Stalker's Leap ability). This is also the case for some Rift Guardians abilities.
- Large monsters such as Golgors or Mallet Lords are immune to any kind of knockback effect.
"Soft" Crowd Controls
These CCs are not affected by crowd control resistance in any way, nor do they have any effect on it. "Soft" crowd control effects are the following:
"Hard" Crowd Controls
As stated earlier, monsters gain 10% Crowd Control Resistance for every second spent under at least one of these effects. "Hard" Crowd Control effects are the following :
Those crowd controls are "Displacement" Effects that give monsters a flat 40% crowd control resistance. Monsters with a crowd control resistance of 65% or above are completely immune to these effects. Yet, any knockback attempt will still trigger the effect of Strongarm Bracers. Nonetheless, we can mention that Cyclone Strike is well-known for not respecting this rule as it does not trigger Strongarm Bracers effect on immune targets.
Crowd Control Resistance Management
Understanding crowd control resistance (CCR) and managing it properly can be gamebreaking in Greater Rift pushing or any higher greater rifts farming, especially for some builds or in groups. So keep in mind that every crowd control needs to have a purpose to be relevant and not disrupting! Whether its a DPS window, an emergency situation (ie. you're about to die) or a pull/buff, any crowd control must be justified.
The AoV Heaven's Fury Crusader (Bracer of Fury) and most Necromancers builds such as the Masquerade Bone Spear Necromancer (Krysbin's Sentence) rely heavily on monsters being under specific crowd controls to unleash their full potential damage. For those builds in solo you mostly use your crowd control skill during your DPS window to maximize your damage.
Using it for no reason in between DPS windows is useless and will prevent monsters from following you when your main objective is to gather monsters. Refreshing a buff or avoiding a death, however, are acceptable reasons to use your control skill.
Some solo builds rely on crowd controls to survive (like Wizard with Halo of Arlyse + Ancient Parthan Defenders), which requires good management of both monster density and crowd control resistance mechanics. If you stand still in the middle of monsters for too long, or fail to reposition in a new pull after proccing Unstable Anomaly, monsters will build resistance and eventually you won't freeze them anymore, losing all benefit from Ancient Parthan Defenders… and suffering a miserable death.
Groups also dislike unwanted crowd controls, because the zBarb needs to use crowd control resistance in order to drag, gather and pixelpull monsters. Spamming controls and knockbacks at the wrong time or place disrupt the efficiency of the group by preventing proper pulling of the monsters; as well as potentially destroying specific DPS windows.
For these reasons, you also want to avoid any secondary affix on your gear that have a chance to proc a specific crowd control. This is especially true for knockback, and to a lesser extent blind and fear as they can make the monster move.
This explains why Speed Pylon is often skipped during high Greater Rifts as it constantly triggers a knockback on monsters around you, rendering them immune to any crowd control within seconds. Its usage is generally restricted to the boss fight in order to let the boss killer stack Bane of the Stricken faster.
Crowd Control mechanics and especially Crowd Control Resistance can be fairly complicated to comprehend. Nonetheless, mastering those mechanics can make a colossal difference in terms of gameplay efficiency. Hopefully this article was helpful and opened you to a whole new world in Diablo III!
Guide by Chewingnom.