"Reduce your skill cooldowns by 2 seconds. You are unlucky." Purity is a lunar item - the direct counterpart to 57 Leaf Clover. It cuts all skill cooldowns by a flat 2 seconds per stack but makes every random effect in the game roll one extra time for an unfavorable outcome. The cooldown floor is 0.5 seconds. The luck penalty is uncapped. One stack is almost always correct.
Cooldown
- 2s flat (+1s/stack)
Counterpart
57 Leaf Clover
How the Luck Penalty Works
Each stack gives -1 luck. Every proc-chance roll in the game is run an extra time for an unfavorable outcome per Purity stack. A 10% chance item with 1 Purity rolls twice - both must succeed to proc, making it effectively harder to trigger.
The penalty is uncapped. More Purity stacks compound the luck penalty indefinitely. 5 Purity stacks means every proc rolls 5 extra times unfavorably - most chance-based items become functionally useless.
57 Leaf Clover cancels it exactly. 
Each Clover gives +1 luck. Equal stacks of Purity and Clover result in 0 net luck. 3 Clovers + 3 Purity = no luck modifier at all.
Tougher Times is immune. 
Tougher Times is explicitly unaffected by luck. Its block chance formula is separate from the luck system. Always safe to stack alongside Purity.
Items with cappable procs are unaffected once capped. Lens-Maker's Glasses, Sticky Bomb, and Tri-Tip Dagger can all reach 100% chance through stacking. Once capped, Purity's luck penalty has zero effect on them.
Cooldown Math
Cooldown Reduction Order
Base cooldown
→
Alien Head (% first)
→
Purity (flat second)
→
Min 0.5s
4s base, 1 Purity
4 - 2 = 2.0s
4s base, 1 Alien Head + 1 Purity
(4 x 0.75) - 2 = 1.0s
4s base, 3 Purity
4 - 4 = 0.5s (floor)
Acrid Neurotoxin (1s), 1 Purity
1 - 2 = 0.5s (floor)
Alien Head Applies Before Purity
% reductions (Alien Head, Light Flux Pauldron) are calculated first, then Purity's flat reduction is subtracted. Always stack Alien Head before relying on Purity for the cooldown floor - the combination is more powerful than either alone.
Good Items with Purity
Lens-Maker's Glasses
Scales to 100% crit - luck penalty irrelevant once capped. Core of most Purity builds.
Sticky Bomb
Can reach 100% proc. Needs more stacks with Purity but cap is achievable.
Tri-Tip Dagger
10% bleed per stack. Reaches 100% with enough stacks. Bleed damage unaffected by luck.
Tougher Times
Completely luck-immune. Stack freely - zero interaction with Purity penalty.
Alien Head
% cooldown applies first, then Purity subtracts flat. Best cooldown pairing.
Bad Items with Purity
AtG Missile Mk. 1
10% proc - cannot reach 100%. Each Purity stack reduces missile frequency further. Drop at Cleansing Pool.
Ukulele
25% chain lightning - cannot hit 100%. Purity actively kills Ukulele uptime.
Bandolier
18% ammo pack on kill. Cannot cap. Purity makes cooldown resets from Bandolier rarer - counterproductive.
Happiest Mask
7% ghost spawn - cannot reach 100%. With Purity, ghost spawns near-disappear at multiple stacks.
Best Survivors for Purity
| Survivor |
Rating |
Why |
 Acrid | S Tier | 1 Purity drops Neurotoxin and Ravenous Bite to 0.5s. Poison/Blight uptime becomes near-constant. Best Purity user. |
 Mercenary | S Tier | Eviscerate at near-zero cooldown is enormous. Melee survivability scales with how often skills fire. |
Most Survivors Benefit - If You Build Around It
Any survivor with skills that scale with cooldown becomes stronger with Purity. Pair it with crit items to neutralize the luck penalty and let the cooldown reduction shine. Avoid Purity on proc-heavy builds that rely on AtG, Ukulele, or Happiest Mask.
How to Unlock Purity (The Calm Challenge)
The Calm - Complete a Shrine of the Mountain
Find a Shrine of the Mountain on any stage, activate it (free), then complete the Teleporter Event with the enhanced boss. The boss will be harder and potentially elite, but each Shrine of the Mountain also rewards an extra item per player. Completing the challenge once permanently unlocks Purity to appear in future runs.
Tips
One stack is almost always enough. The first Purity gives -2s - often enough to floor most skills. Each additional stack adds only -1s more cooldown reduction but the luck penalty compounds. Stack only for extreme cooldown builds.
Build around crit to neutralize the penalty. Stack Lens-Maker's Glasses to 100% crit. Once capped, Purity's luck downside is effectively gone and you keep the full cooldown benefit.
Drop proc items at a Cleansing Pool. If your build has AtG, Ukulele, or Bandolier and you pick up Purity, exchange the weaker items at a Cleansing Pool for greens. Redesign around the Purity.
Purity + Artifact of Command is powerful. Command lets you choose Lens-Maker's Glasses until crit-capped, then Purity's penalty is neutralized. Full cooldown benefit with no downside.
Stacking Purity beyond 3 is rarely worth it. Three stacks reduce most skills to 0.5s floor. More stacks give zero extra cooldown benefit but continue stacking the luck penalty indefinitely.
Frequently Asked Questions
What does Purity do in Risk of Rain 2?
Purity is a lunar item that reduces all skill cooldowns by 2 seconds flat (plus 1 second per additional stack) but makes all random effects roll one extra time for an unfavorable outcome per stack. The minimum cooldown floor is 0.5 seconds. It is the counterpart to 57 Leaf Clover - equal stacks of each cancel out.
How do you unlock Purity in Risk of Rain 2?
Purity is unlocked by completing The Calm challenge, which requires completing a Shrine of the Mountain - activating it and defeating the enhanced teleporter boss. Once unlocked it starts appearing in Lunar Pods and the Bazaar Between Time.
Does Purity affect Tougher Times?
No. Tougher Times is explicitly unaffected by luck. Its block chance is calculated separately from the luck system that Purity and 57 Leaf Clover modify. Tougher Times is one of the safest items to stack alongside Purity.
Does 57 Leaf Clover cancel out Purity?
Yes, directly. Each stack of Purity gives -1 luck and each Clover gives +1 luck. They cancel each other out exactly. 3 Clovers and 3 Purity stacks result in 0 net luck - as if you had neither item.
What items work well with Purity?
Items that can reach 100% proc chance through stacking work best: Lens-Maker's Glasses (crit), Sticky Bomb, and Tri-Tip Dagger all eventually hit 100% regardless of Purity's luck penalty. Alien Head pairs well for compounding cooldown reduction. Avoid proc-chance items that cannot reach 100% like AtG Missile Mk. 1, Ukulele, and Happiest Mask.
How many Purity stacks should I use?
One stack is usually optimal. The first Purity gives -2s cooldown which is often enough to hit the 0.5s floor on short-cooldown skills. Each additional stack adds -1s more cooldown reduction but the luck penalty compounds uncapped. Stack only if your build relies entirely on skills that scale with cooldown and you have crit or other non-luck-dependent items.
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