Ailments, Thresholds, Charms and Immunity in Path of Exile 2

Ailments in Path of Exile 2 split into two groups. Damaging ailments deal damage over time and have their own damage-dealing rules; non-damaging ailments apply a control or debuff effect without a damage-over-time component.

Damaging ailments are Bleed, Poison and Ignite. Non-damaging ailments are Chill, Freeze, Shock, Electrocute and Stun-related effects. Each appears as an icon in your status bar when active; the icon tells you what is happening and how urgent it is.

• Bleed: physical damage over time, usually from attacks; shows a bleeding icon.
• Poison: chaos damage over time that stacks with each application; shows a venom icon.
• Ignite: fire damage over time; shows a burning icon.
• Chill: slows your action speed by a scaled amount; shows a frost icon.
• Freeze: briefly stops actions entirely; shows a frozen icon.
• Shock: increases damage taken from hits; shows a lightning icon.
• Electrocute: a heavier shock-like stun effect; shows a charged icon.
• Stun: interrupts action when the stun meter fills; shows a staggered icon.

Four concepts govern every ailment. Buildup is the meter that fills as you deal ailment damage; once buildup reaches the target's Threshold, the ailment is applied and the meter resets. Magnitude scales how strong the effect is (for example how much Chill slows you, or how much Ignite damages). Duration is how long the applied ailment lasts.

Threshold is the gate: a target with a high threshold needs more buildup to be afflicted. Player base Ailment Threshold is a portion of Maximum Life, while bosses tend to have much larger thresholds, so the same skills that reliably ail a pack may never stick to a boss.

• Buildup: fills toward the Threshold; reaching it applies the ailment.
• Threshold: the target value buildup must meet before the ailment lands.
• Magnitude: how severe the effect is once applied (slow %, DoT, etc.).
• Duration: how long the ailment remains active before expiring.

You apply ailments by dealing the matching damage type with a hit or damage-over-time effect. The chance to apply is governed by ailment chance and the enemy's threshold; enough buildup crosses the threshold and the ailment lands.

Some skills and supports are built specifically to apply ailments (for example bleed supports on attacks, or ignite-from-fire spells). Against bosses, investing in ailment magnitude and threshold-breaking modifiers matters far more than against normal monsters.

• Match the damage type to the ailment you want (fire to Ignite, cold to Chill/Freeze, etc.).
• Buildup must reach the target threshold; bosses have higher thresholds.
• Magnitude improvements make the effect stronger, not easier to apply.
• Check the in-game tooltip for the exact buildup and threshold numbers on a given enemy.

Defences against ailments are layered, and each layer behaves differently. Resistance lowers the magnitude or damage of an ailment but does not stop it from applying. Reduced Effect and Reduced Duration shrink the ailment's impact or how long it lasts. Avoidance can prevent the ailment from being applied in the first place on a roll.

Immunity is the strongest layer: it fully prevents the linked ailment from affecting you, regardless of buildup. Resistance and immunity are not interchangeable - capping fire resistance will not stop you being Ignited, it only reduces the burn.

• Resistance: reduces magnitude/damage, ailment can still apply.
• Reduced Effect / Reduced Duration: shrinks or shortens the ailment.
• Avoidance: chance to prevent application entirely.
• Immunity: fully prevents the linked ailment (Charm or keystone).

A Charm is a trinket carried in a Belt that watches for a specific condition and fires automatically when that condition occurs. An Immunity Charm triggers and fully prevents the linked ailment; a Resistance Charm instead grants a temporary resistance boost when its trigger hits.

Each Charm consumes Charges when it triggers. Charges are stored only while the Charm is in a Belt, and they refill at Wells or by killing monsters. A Belt provides a limited number of Charm sockets, so you cannot equip every Charm at once - choose by the content you are running.

• Auto-trigger: fires the moment its linked condition happens.
• Charges: consumed on use; refill at Wells or by kills.
• Belt sockets: a limited number of Charm slots (see in-game Belt tooltip).
• Immunity vs resistance: immunity prevents, resistance only reduces.

Bosses are meaningfully harder to afflict than regular monsters. Their larger ailment thresholds mean more buildup is required, and many boss fights are tuned so that ailments that trivialise trash mobs barely register.

Because of this, avoid claiming a boss is fully immune or fully controllable unless a current source confirms it. Treat boss ailment application as possible-but-difficult, and verify specific cases against the live client rather than assuming.

• Boss thresholds are larger, so buildup often falls short.
• Some bosses resist or shrug off certain ailments by design.
• Do not state absolute 'immune' or 'controllable' claims without a current source.
• Verify boss-specific ailment behaviour in-game before relying on it.