PoE2 Delirium Guide: How Fog Density Multiplies Your Simulacrum Rewards (Wave-by-Wave Breakdown)

Quick Start: Delirium in 5 Steps

Before the mechanics, here’s what you do first:

1. Find a Delirium Mirror on any Waystone map — it appears near the entry point as a standing mirror
2. Interact to start the fog — you have exactly 4 seconds outside the mist before the encounter resets
3. Follow the fog toward the boss — the mist advances in the direction of the map boss; clearing enemies as you go fills your reward bar
4. Grab Fractured Mirror Shards as they spawn at fog-depth thresholds — purple shards boost loot, red shards open Loathsome Mire
5. Kill the map boss under fog — consistent boss kills accumulate Deliriousness and eventually unlock Simulacrum content

Verified on Path of Exile 2 patch 0.5.2 (June 2026). Values may change with future updates.

What Delirium Is — and What Changed in Patch 0.5

If you’re new to PoE2 generally, our Path of Exile 2 Beginner’s Guide covers class selection and currency basics before you reach endgame systems. Delirium specifically: it’s a fog-based encounter where interacting with a Delirium Mirror fills your map with grey mist, additional monsters, and escalating difficulty tied to a zone-level progress metric called Deliriousness.

Patch 0.5.0 (Return of the Ancients) transformed Delirium from a simple fog mechanic into a full endgame system [1]. The biggest change: the Simulacrum dropped from 15 waves to 7. GGG also added a visible progress bar showing fog depth and time remaining, Fractured Mirror Shards that spawn at depth thresholds rather than on timers, five new Elite Delirium Monsters, and Trial of Madness — which pushes Deliriousness past the 100% standard cap toward a 200% maximum [1]. Patch 0.5.2 then halved the toughness and damage bonuses monsters gain inside the fog, making high-Deliriousness runs survivable for more builds [3].

How Fog Density Actually Works

Fog density is tracked as your Deliriousness percentage — a zone-level modifier that accumulates the more Delirium encounters you complete in a connected foggy region. You start at 10% Deliriousness on your first mirror interaction. Each completed Delirium map in that region adds +1% [2]. Hit 100% and Simulacrum content becomes accessible.

That Deliriousness number drives three separate reward levers simultaneously:

• Monster power — enemies gain proportionally more life, damage, and toughness at higher Deliriousness. Post-0.5.2, these bonuses are roughly half what they were at launch, but they still scale meaningfully past 80%
• Distilled Emotion quality — higher Deliriousness shifts emotion drops toward rarer types. At low Deliriousness you see mostly Disgust and Envy; at peak you see Isolation and Suffering variants, which are worth significantly more in trade
• Mirror Shard unlocks — Fractured Mirror Shards spawn when you hit specific depth thresholds inside a fog encounter, not on a clock [3]. Reaching the threshold faster opens more shard opportunities per run

The fog itself moves toward the map boss. Your job is to follow it, killing enemies as you go. Step outside the mist for more than 4 seconds and the encounter ends — immediately, no grace period [2]. That 4-second timeout is the hidden constraint most new Delirium players collide with first: the fog advances on its own schedule and doesn’t wait for you to finish a rare monster pack.

Fog Density vs Mob Density: Which Actually Multiplies Your Rewards?

The most common Delirium misconception is that running the mechanic on dense maps — ones packed with enemy packs — is the primary reward driver. Mob density is a volume play. Fog density (Deliriousness %) is the quality multiplier.

Here’s the mechanism: the Delirium reward engine scales on how tough the monsters you kill are and how rare they are. Both factors are tied directly to your accumulated Deliriousness, not to raw enemy count. A moderately packed map at 80% Deliriousness will consistently outperform a dense map at 30% Deliriousness for Distilled Emotion quality — the monsters you kill at 80% simply drop rarer emotion types.

The practical consequence: don’t skip Delirium encounters because a map looks sparse. Every completed encounter adds +1% Deliriousness to your zone [2]. Skipping maps wastes the compound-interest structure of Deliriousness building. Run every mirror you see in order, in the same region, and let it accumulate.

Where mob density genuinely matters: Simulacrum Splinters only drop from Tier 11+ Waystones. Once you’re actively farming Splinters, higher pack size means more total drop opportunities per map. But that’s a throughput play for Splinter collection — it doesn’t shift the quality of individual monster drops. For Liquid Emotion crafting, fog density is what determines what you get.

If your current build struggles to keep pace with the fog, our PoE2 League Starter Builds guide covers high-clear-speed options that work well in Delirium without requiring expensive gear investment.

Simulacrum: Wave Structure and Reward Scaling

The Simulacrum is Delirium’s dedicated endgame arena. Collect 300 Simulacrum Splinters — which drop from Tier 11+ Waystones only after allocating the “Is This About Me or You?” atlas passive [2] — then activate at the Realmgate. Three difficulty tiers exist:

Patch 0.5.0 reduced the wave count from 15 to 7 [1], but added randomized negative modifiers to each wave — effectively map mods applied mid-run. Each wave escalates Deliriousness by 5%, so the power curve is relatively gentle in Waves 1–2 and aggressive in Waves 5–7.

Waves 1–2 (Calibration Phase): Lowest Deliriousness, standard Distilled Emotion drops dominate. Use these waves to establish your flask rhythm and identify which wave modifiers are dangerous for your build. Don’t panic-click through these — mistakes in Waves 1–2 often carry into the later waves where they’re fatal.

Waves 3–4 (Mid-Run): Kosis, the Revelation — a caster-type Delirium boss — begins spawning from Wave 3 onward, with spawn frequency increasing each wave. (Community testing places first appearances in this range; treat this as a pattern-based observation and verify in-game, as spawn timing can vary with atlas allocation.) Emotion drops begin shifting toward Concentrated variants here.

Waves 5–6 (High Deliriousness): Omniphobia, the Fear Manifest enters the rotation. Monster toughness at this Deliriousness range means one positioning mistake can cascade into a death. Potent Emotion drops become possible in these waves — these are the high-value Liquid Emotions used for Decanter of Madness crafting and worth meaningfully more than Standard variants.

Wave 7 (Final Wave): Completing Wave 7 grants 2 Atlas Passive Points and a boss key for Tangmazu, the Raven Trickster — Delirium’s pinnacle boss with approximately 7 million health across forms and a high-damage blast attack at roughly 50% health [4]. Simulacrum-exclusive drops, including Raven’s Reflection, only come from successful Wave 7 completion. You receive one free death per run; a second death ends the attempt entirely.

For most currency-focused players: Merciless Simulacrum starts at 45% Deliriousness, so even Waves 1–2 already have meaningful drop quality. The 150-splinter entry cost is steep, but the per-run yield reflects it. Normal Simulacrum at 50 splinters is the right entry point until your build can clear Waves 5–7 of Merciless without burning the free death on an avoidable mistake.

For a broader look at which endgame mechanics stack well with Delirium, our PoE2 Currency Farming Guide covers the full endgame income picture.

Atlas Passive Priorities for Delirium

The Atlas Passive Tree determines whether Delirium functions as a productive farming loop. Allocate in this order:

1. “Is This About Me or You?” (First priority, mandatory): Without this node, Simulacrum Splinters don’t drop from level 75+ Delirium encounters at all [2]. Nothing else matters until this is active.
2. Slower Fog Dissipation (“You Can’t Just Wake Up From This One”): Extends the 4-second timeout. On larger maps, this is the difference between consistently staying in fog and losing encounters to traversal time between enemy packs.
3. “They’re Coming To Get You”: Rare monsters spawn 25% more often, and slaying a Rare pauses the fog timeout for 4 additional seconds. These effects compound — more Rares means more pause windows, which means longer sustainable encounters and better emotion drop quality per run.
4. “You Can’t Scare Me Anymore”: Unlocks Potent Emotion drops from Unique enemies. Only worth allocating once your build can reliably reach Waves 5–6 of Simulacrum, where Unique enemies appear at meaningful density.
5. “I See Your True Nature Now!”: Activates blue mirror shards that spawn bonus bosses. Valuable but situational — allocate after the four above once your core loop is stable.

For the full endgame atlas passive allocation across all content types, see our PoE2 Atlas Progression Guide.

Delirium Strategy by Player Type

5 Mistakes That End Delirium Runs

Most failed Delirium encounters don’t end with one catastrophic mistake. They end because of accumulated micro-delays that let the fog leave you behind.

1. Stopping to loot mid-encounter: Item pickup breaks your movement. The fog doesn’t pause. Loot after the encounter ends — items stay on the ground, and you can collect them once the fog dissipates.
2. Fighting one rare monster for 30+ seconds: At higher Deliriousness, rares gain enough bulk that slow single-target builds can waste critical time. If a rare isn’t dying within 10 seconds, move on and return after the boss if the fog allows.
3. Following a side room: The fog advances in one direction. A side-room detour often puts you outside the fog boundary before you realize it, ending the encounter without warning.
4. Clicking a Red Fractured Shard at low flasks: Red shards transport you immediately to Loathsome Mire, a boss arena. Without full flask charges and a recovered health pool, this is an unplanned death on a boss you weren’t ready for.
5. Skipping mirrors to wait for a better map: Each skipped encounter is a lost +1% Deliriousness. The compound effect of running every mirror in a foggy region consistently outperforms selective running every time. There’s no such thing as “saving” your Deliriousness progress — the only way to build it is to play it.

PoE2 Delirium: Frequently Asked Questions

Can I re-enter a Delirium encounter after leaving the fog?

No. Once you’re outside the mist for more than 4 seconds, the encounter resets [2]. You don’t retain any Deliriousness progress from that specific run, and the map boss is no longer counted as Delirious. The only way to build Deliriousness progress is to complete encounters, not re-attempt them after breaking the fog boundary.

How many maps does it take to collect 300 Simulacrum Splinters?

Community testing with an optimized Delirium atlas suggests roughly 20–30 Tier 11+ maps per Simulacrum when running “Is This About Me or You?” and “They’re Coming To Get You” (extra Rare spawns) [4]. That’s a pattern-based estimate — your actual rate varies with build clear speed, map pack size, and current Deliriousness. Treat it as a rough benchmark, not a fixed rate.

Should I use Distilled Emotions for amulet anointing or sell them?

Sell the most common types early (Disgust, Envy, Paranoia) — they have consistent floor value in trade. Don’t commit emotions to the Decanter of Madness until you know exactly which Instilled Notables you’re targeting. Wasting a set of Isolation or Suffering on the wrong notable is a significant currency loss. Once you’ve identified your target, remember that three matching emotions upgrade to the next tier at the Reforging Bench — so stockpiling before committing is almost always worth it.

Sources

1. Path of Exile 2 Content Update 0.5.0 — Return of the Ancients Patch Notes — pathofexile.com
2. Delirium Guide — Maxroll.gg PoE2 Resources
3. Path of Exile 2 Patch 0.5.2 Patch Notes — pathofexile.com (via maxroll.gg/poe2/news/0-5-2-patch-notes)
4. PoE2 Delirium Farming Community Testing — boostmatch.gg / timesaver.gg (community guides, Tier 4 data)

Michael R.

I've been playing video games for over 20 years, spanning everything from early PC titles to modern open-world games. I started Switchblade Gaming to publish the kind of accurate, well-researched guides I always wanted to find — built on primary sources, tested in-game, and kept up to date after patches. I currently focus on Minecraft and Pokémon GO.