Crowd Control Explained
Last Updated:May 21, 2023|Changelog
Introduction
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. Do not hesitate to check out the Elite Affix Mechanics and Special Monster Mechanics articles by Wudijo for more information!
"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:
- Crusader
- Akarat's Champion
- Laws of Justice Bravery
- Iron Skin
- Monk
- Epiphany
- Serenity
- Inner Sanctuary Temple of Protection
- Near Death Experience
- Necromancer
- Bone Armor Limited Immunity
- Wizard
- Archon
- Barbarian
- Wrath of the Berserker
- Ignore Pain
- Nerves of Steel
- Demon Hunter
- Vengeance
- Smoke Screen
- Awareness
- 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
General Rule
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 after the Charm ends, 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).
CC Stacking
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.
Knockback Effects
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:
These effects will slow down monsters' movement speed. The distinction to keep in mind is that a Chill is always a Slow, originated from a Cold-related source in most scenarios, but a Slow is not necessarily a Chill.
By default, slow and chill inflict a 30% movement speed reduction to the target but the tooltip of the skill or item used can state a higher magnitude (60% or 80%). That being said, most skills produce a 60% movement speed penalty when the tooltip does not state the slow amount. The Necromancer however has specific 75% slow effects with Decrepify and Siphon Blood Suppress, or can stack a 10% slow up to 5 times with Corpse Lance Shredding Splinters.
However, there is no slow that goes above 80%, except the Barbarian's Threatening Shout Intimidate in combo with Horde of the Ninety Savages (2) Bonus which applies a tremendous 90% movement speed slow.
Decrepify Enfeeblement has a special mechanic that slows the monster at 100% on application (which effectively roots the monster) and decays by 5% every second until it reaches 75% slow after 5 seconds.
Furthermore, skills that inflict a chill or slow more often than not say so in their tooltip but there are quite a few inconsistencies to mention:
- Haunt with any rune inflicts a 60% chill.
- Spirit Barrage with any rune except Well of Souls causes a 60% chill.
- Zombie Charger Lumbering Cold inflicts a 2 second 60% slow.
- Gargantuan Humongoid's Cleave triggers a 1 second chill, which can be extended to any rune through the use of Spite.
- Ground Stomp Deafening Crash, Avalanche Snow-Capped Mountain, Corpse Spiders Medusa Spiders and Ray of Frost with any rune trigger a chill while the tooltips say "slow".
- All Wizard's Cold skills besides Black Hole Absolute Zero apply a 1 second 60% chill even though the tooltip does not state anything:
- Arcane Orb Frozen Orb
- Blizzard with any Cold Rune.
- Energy Twister Mistral Breeze
- Familiar Icicle
- Frost Nova Frozen Mist (chill refreshes as long as monsters are located in the mist)
- Hydra Frost Hydra
- Magic Missile Glacial Spike
- Meteor Comet (chill refreshes by the impact's icy mist)
- Shock Pulse Explosive Bolts
- Spectral Blade Ice Blades
Meanwhile slows and chills are unrelated to crowd control resistance, all non-normal monsters have an innate 25% resistance to slow effects (as well as a 65% resistance to Attack Speed penalties). For instance, this means that a 60% chill or slow only applies a 60 * (1 - 0.25) = 45% movement speed penalty to champions, minions, rare elites and bosses.
This effect can be considered a soft crowd control in a way. Daze (or interrupt) simply aborts the current monster animation and causes a short "stagger" animation. Yet, it does not trigger any crowd control resistance nor is it affected by it. This effect is tied to a hit recovery system but the exact rules behind it stay undetermined.
Way of the Hundred Fists with any rune is the only known source able to trigger this effect reliably and it is actually a hidden effect. Indeed, every second strike of this skill causes the interrupt on every monster hit. This effect can only apply to normal monsters. It can be used to greatly mitigate incoming damage, especially to interrupt dangerous attacks like Mallet Lords slams, Dark Berserkers hammer slams or Savage Beasts and Bogans charges.
"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 :
These are grouped because they are extremely similar: the monster will be locked in place, unable to perform any action during the effect. Stuns and Freezes are the most common crowd controls in Diablo III and every class has access to them. Fun fact: the Rift Guardian Man Carver stuns himself for a short period after performing his Charge attack!
Some mechanics only interact with one or the other and will state so. However, although Ancient Parthan Defenders and Dovu Energy Trap only specify stuns in their tooltip, they also work with freezes.
Chance to Stun on Hit is a secondary affix that can be found on Gloves, Weapons, Offhands as well as some items like Sledge Fist; meanwhile Chance to Freeze on Hit is accessible on Belts, Weapons, Offhands and legendaries such as Azurewrath. Both affixes procs a 2 seconds stun or freeze after the hit, are affected by proc coefficient, and several sources of the same affix stack multiplicatively.
Land of the Dead Frozen Lands is a case worth mentioning. When active it pulses twice a second, applying a 10 second freeze to all enemies in line of sight within 60 yards range. This means Frozen Lands will instantly cap monsters at 100% CCR, rendering them immune to other crowd controls until they drop this resistance.
Blind renders the monster unable to perform any action during the effect, yet it can still move around slightly. Monk's Blinding Flash and Crusader's Shield Glare are the main sources of this type of Crowd Control. Cluckeye special effect is a chicken that applies a 2 second Blind and a Knockback to its target, which is very useful on the Scoundrel to crowd control Rift Guardians for instance.
Chance to Blind on Hit can appear on Weapons, Offhands and Amulets. Blind Faith and The Sultan of the Blinding Sand can roll this affix up to 40%. It triggers a 2 seconds blind after the hit and is affected by proc coefficient. If you have several sources of Blind on Hit, they stack multiplicatively.
Hex is a special Blind effect that is only accessible through the Witch Doctor's Hex and the Enchantress follower's Mass Control. It turns enemies into chickens (or pigs with Jinx) that wander around for 3 seconds.
Dinner is ready
Feared monsters run away in random directions and have a skull above their head as visual effect. Witch Doctor's Horrify has a specific mechanic that fears and roots the monster at the same time. In combination with Tiklandian Visage, Horrify reapplies its effect every 0.6 seconds for 6-8 seconds.
Chance to Fear on Hit is a secondary affix that can be found on Helmets, Weapons, Offhands as well as Echoing Fury, Rechel's Ring of Larceny and Pandemonium Loop. This is a 3 second fear applied after the damage hit. This affix is affected by proc coefficient and multiple sources of this affix stack multiplicatively.
Even though this effect has two names, Charm and Confusion are the same effect. Confused monsters attack other monsters mostly using basic attacks (they can also cast Elite Affixes), and other monsters will attack them back. They won't attack the player and either stand still or follow the player if they have no target to attack. It is still possible for the player to attack them but not to inflict them with another crowd control.
Charm is not a very common crowd control with the only sources being Mass Confusion, Weapon Throw Stupefy, Shield Glare Uncertainty, Henri's Perquisition, Overwhelming Desire, Skull of Resonance, The Tormentor and the Enchantress' Charm. Noteworthy case, Skull of Resonance has 25% chance to apply a 15 seconds Charm to enemies when you cast Threatening Shout, and gets buffed to a tremendous 30 seconds with the passive Inspiring Presence!
Immobilize is a root that is essentially a 100% slow effect. Immobilized monsters can still perform actions but cannot move at all. Some monster abilities can break root effects such as Corrupted Angel's Dash. Main sources of immobilize in the game are:
- Crusader's Judgment & Smite Shackle
- DH's Caltrops Torturous Ground
- DH's Spike Trap Impaling Spines
- Chance to Immobilize on Hit on Boots
- Hellrack
- Stone Gauntlets
Chance to Immobilize on Hit triggers a 2 seconds root after the hit. This affix is affected by proc coefficient and multiple sources of this affix stack multiplicatively. Although Immobilize does not have an obvious visual effect, remember that Rift Guardians are affected by Immobilize and build CCR accordingly!
Judgment visual effect
Taunted monsters run towards and attack you. Taunt's visual effect lasts for 2 seconds no matter what, which can trick you into thinking it does not work properly. It works and is still a hard CC so don't forget the crowd control resistance gained by the monster is tied to the duration of the taunt used, regardless of the visual effect's duration. For instance, Threatening Shout Demoralize applies 40% crowd control resistance, even up to an insane 80% when combined with Horde of the Ninety Savages (2) Bonus.
We can also mention Lure, which is essentially a taunt with a slight twist because it draws all lesser (normal) monsters within 25 yards to a skill you cast rather than drawing them to you. There are only 2 existing cases: The Smoldering Core that lures to your Meteor impacts and Chanon Bolter that draws them to your Spike Traps.
Monsters lured to Meteor impacts
Mesmerize is a unique crowd control available only through Halcyon's Ascent:
- Has a 30 yards radius.
- On activation triggers a 1 second taunt.
- Twice a second for 6-8 seconds, attempts to knockup the monster.
- The Mesmerize effect is not a Hard Crowd Control in itself. Its duration is not affected by Crowd Control Resistance.
- Due to monster animations, the knockup happens once per second and prevents any further displacement for the duration. With Land of the Dead Frozen Lands the visual knockup happens twice a second due to the freeze preventing the monster animations. Freeze effects can sometimes prevent the monster from being visually knocked up.
- Every knockup attempt activates Strongarm Bracers effect.
- It seems every successful knockup is considered a hard crowd control instead of a displacement effect. This means the normal rules apply: if the monster goes through a 1.2 second knockup/land/recovery animation cycle, it gains 12% crowd control resistance. This explains why Halcyon's Ascent Knockups completely ignore the knockback immunity threshold at 65% or above crowd control resistance.
Knockback Effects
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.
Knockbacks push back the monster affected. Knockup is essentially the same as Knockback, but the monster is knocked up in the air. The main use of these control impairing effects is to benefit from Strongarm Bracers. Good examples here are Deadly Reach and Vault Rattling Roll.
These abilities are displacements that allow you to control the position of the monsters. As a result, pulling and grouping (packing) abilities are amongst the strongest control impairing effects in the game as they can drag and position monsters at will or even group them together.
Thus these abilities are popular in Greater Rift pushing, especially in groups, to gather many monsters together and pixelpull them in order to maximize Area Damage and damage output of abilities/builds scaling with density such as the Spirit Barrage Witch Doctor.
Energy Twister with Ranslor's Folly, Brigg's Wrath, Piranhas Piranhado, Ancient Spear Rage Flip or Ground Stomp Wrenching Smash are good examples of widely-used grouping abilities and mechanics.
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.
Conclusion
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!
Credits
Written by Chewingnom.