PoE2 Blight Farming Guide: Chokepoint Tower Placement for All 5 Map Layout Types

Blight encounters are one of the tightest tower-defense systems in any ARPG, and they punish a single bad tower placement more harshly than almost any other mechanic in Path of Exile 2. Clear the pump and you walk away with oils, Blighted Maps, and solid currency. Miss one lane and watch five minutes of work collapse in under thirty seconds.

This guide covers the mechanic from first principles, but the section most players need — and that no existing guide provides — is the map layout geometry breakdown. The reason Toxic Sewer clears trivially while Dunes turns into a scramble has nothing to do with monster difficulty. It comes down to how many tendrils spawn and whether the map forces them through a chokepoint. Once you understand the five layout types, tower placement becomes predictable instead of reactive.

Verified against PoE2 patch 0.5.2 (June 2026). Tower values and oil drop rates may shift with future updates — check the official patch notes for changes after this date.

Blight in PoE2: What You Need to Know in 2026

Blight spawns as a random encounter in PoE2 maps — look for Sister Cassia standing near a glowing fungal growth. As of patch 0.5.2, Blight is not one of the dedicated Atlas endgame mechanics you can stack via tablets (those slots go to Breach, Ritual, Delirium, Expedition, and Runes of Aldur). It appears as a random map event, similar to how it worked in early leagues in Path of Exile 1.

PoE2 game data confirms the full Blight encounter structure is present: portals coded by damage type (Fire, Cold, Lightning, Physical, Minion), tendril paths, a central core element, and the boss indicator — all the components from PoE1. The mechanics described below apply directly to PoE2 encounters.

For atlas-wide Blight farming via tablets, check back when GGG formally integrates it as a dedicated league activity. Until then, the best way to run Blight consistently is to use Atlas passive tree nodes that increase league mechanic spawn rates in general.

Quick Start: Blight Encounter Checklist

1. Talk to Sister Cassia before clicking the fungal growth — she drops the pump and the encounter begins immediately on click.
2. Check the portal icons at each tendril spawner before placing any tower. Fire icon = fire-resistant lane; Minion icon = summoned minions ignored by your Summoning towers.
3. Spend starting resources on Seismic or Chilling towers first, not damage towers — stall buys time, damage does not.
4. Place your first tower cluster at the closest natural chokepoint to the pump, not at the spawners.
5. Drop an Empowering Tower adjacent to every tower cluster before upgrading individual towers past tier 2.
6. Never upgrade past tier 2 before you have Empowering coverage — unbuffed tier 3 towers underperform buffed tier 2 towers.
7. Keep one Seismic or Stone Gaze tower free for boss lanes — bosses ignore most CC except these two.
8. If the pump is about to break, switch to active play (killing enemies yourself). Towers alone will not recover a losing position.

How the Blight Mechanic Works

Sister Cassia throws a Purification Pump near the fungal growth. Tendrils grow outward from the core, and at the end of each tendril a portal spawns enemies who follow the exact path of the tendril back to the pump. Enemies take no shortcuts — they walk the line, which means you always know where they will be.

The pump has 10 durability in standard Blight encounters. Durability lost per enemy that reaches the pump: normal monsters remove 1, magic remove 2, rares remove 5, and unique monsters remove the full 10 — one unique gets through and the encounter is over [2]. This is why rare and unique enemies on undefended lanes are instant-fail states.

You earn resources at the start of the encounter and by killing blighted enemies. Resources build towers (100 per base tower) and upgrade them (150 / 300 / 500 for tiers 2 through 4). Towers have a maximum effective radius of roughly two screen-widths from the pump — building beyond that range wastes resources on towers that lose function.

Critical mechanic: the number of tendrils that spawn is determined by how much open area surrounds the pump when Cassia drops it. In a narrow sewer map, the roots have nowhere to grow and you get 2-3 tendrils. In an open-field map, the roots spread in all directions and you can face 7-8 simultaneous lanes. This single fact explains every map selection recommendation in this guide.

The 6 Tower Types and When to Build Each

Each tower category splits into two tier-4 upgrade paths. Build the stall towers first (Chilling, Seismic, Summoning), then add damage only after stall is covered. An Empowering Tower adjacent to any cluster before upgrading past tier 2 is never a wasted resource [6].

The 5 Map Layout Types: Chokepoint Geometry Guide

This is where most Blight guides stop at “pick narrow maps” without explaining the geometry. The layout type determines where your chokepoint is, how many resources you need, and which towers are mandatory versus optional. Learn these five patterns and you can read any map on entry [1][3][4].

Type 1: Linear Corridor

Example maps: Toxic Sewer, Strand, Canyon, Colonnade

Geometry: The pump drops in a narrow passage with walls on both sides. Tendrils can only grow forward and back along the corridor — you get 2-3 lanes total, all traveling roughly in parallel through the same choke zone.

Optimal chokepoint position: Build 60-70% of the way from the spawner to the pump. Close enough that your towers cover the full corridor width, far enough that you have time to see slow-moving rares before they reach the cluster.

Tower priority: Two Chilling towers side by side covering the corridor width, one Empowering Tower adjacent, one Fireball (upgrade to Flamethrower for short lanes). This setup handles linear corridors solo. Reserve one Seismic for any rare or boss that punches through the slow.

Why it’s the best layout type: Every enemy from every lane funnels through the same 3-4 tile-wide strip. Your AoE hits all lanes simultaneously. Resource efficiency is roughly 3× higher than open field because you’re buying one cluster that does the work of three [5].

Type 2: Hub-and-Spoke (Radial)

Example maps: Core, Cemetery, Infested Valley

Geometry: The pump drops in an open central area with tendrils radiating outward like spokes on a wheel. You can face 5-7 lanes with no natural convergence point between spawner and pump.

Optimal chokepoint position: There is no mid-path chokepoint. Instead, build a defensive ring 1-2 tiles from the pump itself — this is your last line of control and the only position where an Empowering Tower can cover all incoming lanes simultaneously.

Tower priority: One Seismic (Temporal) at the pump center, then Chilling towers spaced around the ring for each spoke direction. Summoning towers (Sentinel) between spokes to intercept enemies that slip past the ring. This layout costs significantly more resources than a corridor — plan to use all your economy.

Why Core sees mixed results: Core has the fewest tendrils of any map due to the tight dungeon space near the pump, but the boss is powerful and all lanes converge at once. Use Stone Gaze (Seismic T4 Path B) specifically on the boss indicator lane.

Type 3: Indoor Branching Corridors

Example maps: Haunted Mansion, Underground River, Museum, Vaal Pyramid, Temple of Atzoatl

Geometry: Multiple corridors with T-junctions and 90-degree turns. Tendrils follow the architecture and must turn corners — this is what makes these maps the best in the game for Blight farming. Every T-junction is a natural chokepoint where two lanes merge before hitting the pump.

Optimal chokepoint position: Place your primary tower cluster directly at each T-junction. Enemies from two separate tendrils pass the same tile as they turn the corner. A single Glacial Cage tower at a T-junction covering both branches incoming is equivalent to two towers on a radial layout [3].

Tower priority: Glacial Cage (Chilling T4 Path B, pure CC) at junctions + Scout (Summoning T4 Path B) flanking the junction from the corridor straight-run + Empowering covering both. One Stone Gaze at the junction nearest the pump for bosses.

Why this layout type outperforms corridor: Junction geometry multiplies tower efficiency. One Glacial Cage at a T-junction does the work of two chilling towers on two separate linear lanes — you get more coverage per resource. Haunted Mansion, in particular, has 2-3 T-junctions within Empowering range of a single tower, making it arguably the highest-efficiency Blight map in the game.

Type 4: Open Field / Arena

Example maps: Dunes, Mesa, Waste Pool (outer sections), Ashen Wood

Geometry: Large open areas with minimal walls. The pump gets 6-8 tendrils spreading across the full area. No natural chokepoints exist between spawner and pump.

Optimal chokepoint position: You cannot establish a single chokepoint. Instead, build individual lane stations at the first third of each tendril (close to spawners), and a secondary pump-side ring for anything that gets through. Total tower count is 2× a linear map — budget accordingly.

Tower priority: Temporal (Seismic T4 Path A) near the pump as a wide slow aura hitting all incoming lanes. Chilling towers at each lane’s mid-point. Summoning towers (Sentinel) between lanes as physical blockers. Skip Shock Nova entirely — your resources are too tight for secondary damage towers.

When to run this layout: Avoid open-field maps for oil farming unless you have anoint bonuses for reduced tower cost. The resource drain runs you dry before the encounter ends. If you land on Dunes anyway, prioritize active play (killing enemies yourself) more heavily than tower management — these maps are designed to require a capable build, not just good tower placement [5].

Type 5: Circular / Looping Route

Example maps: Promenade, Coves, Shipyard, Pier

Geometry: The map has an outer ring or arc structure. Some tendrils travel the long way around the ring before converging near the pump. Enemies spend a long time on the outer arc, giving you build time, then suddenly several lanes merge as they approach the pump’s side of the loop.

Optimal chokepoint position: Two positions: (a) mid-arc on the longest tendril path — this is where enemies bunch up during their arc travel, and one tower here gives you 15-20 seconds of extra kill time. (b) The convergence funnel where outer-arc lanes all merge before reaching the pump — this is your last-line cluster.

Tower priority: Stone Gaze (Seismic T4 Path B) at the outer-arc mid-point to hard-stop boss spawns before they reach the convergence. Chilling + Empowering at the convergence funnel. Scout towers (Summoning T4 Path B) on the arc itself — their 10 flying ranged minions cover wide areas without needing precise lane alignment.

The pitfall: New players see enemies far away on the outer arc and assume they have time. The arc convergence hits all lanes at once in under ten seconds once enemies round the corner — build the convergence cluster first, outer-arc tower second [4].

Tower Placement Decision Tree by Resistance Symbol

Before placing your first tower, check the portal icons at each tendril spawner. Build the wrong element into a resistant lane and you’re wasting resources on towers that deal zero effective damage [4].

• Fire icon at portal → No Fireball, Flamethrower, or Meteor towers on this lane. Use Chilling + Seismic instead.
• Cold icon → No Chilling, Freezebolt, or Glacial Cage. Use Fireball or Shock Nova for damage.
• Lightning icon → No Shock Nova, Arc, or Lightning Storm. Seismic and Chilling are safe.
• Physical icon → No Seismic, Temporal, or Stone Gaze damage. Use elemental damage towers; note that Seismic stun is still useful even with physical resistance.
• Minion icon → Summoning towers are ignored entirely — their minions are not attacked but also will not engage the portal’s monsters. Skip Summoning on this lane.
• No icon → Build any tower you want; use this lane to practice your highest-efficiency combo.

Player Type Strategy Guide

Want to understand which currency you get from Blight versus other endgame mechanics? Our PoE2 currency tier list ranks Blight oils against other farming methods by divines-per-hour.

Oil Farming and Blighted Maps

Every cleared Blight encounter drops oils from reward chests at the end of each tendril. The chest count equals the number of tendrils you defended — more lanes, more chests, but also more difficulty. This is why Indoor Branching and Linear Corridor maps are the sweet spot: enough tendrils to get 3-5 chests without the open-field resource drain.

Oil tiers run from Amber (lowest) through Golden (highest), with 15 tiers total. Three oils of any tier vendor-convert to one oil of the next tier up — run this conversion whenever you have 9+ of a single tier. Oils have two uses: anoint a ring with 2 oils to add a tower modifier (reduced cost, increased damage, extended range), or anoint an amulet with 3 oils to unlock any Notable passive from the skill tree without spending a point [2].

Blighted Maps are a separate item tier that drops from Blight chest rewards. They replace all normal content with a single large Blight encounter (5-minute timer, 20 pump durability instead of 10) and reward significantly more oils and currency. Run Blighted Maps on Indoor Branching or Linear Corridor layouts only — dropping a Blighted Map on an open-field map layout is one of the fastest ways to fail a high-investment encounter. See our PoE2 currency farming guide for where Blighted Maps rank in overall farming strategy.

Blight-Ravaged Maps (the highest tier, dropping from Tier 13+ Blighted Maps) allow up to 9 anointments on the map itself and feature 200% increased monster life. These are endgame-character-only content — do not attempt without a build that can solo-clear red map encounters quickly. See the endgame mapping guide for gear thresholds before running Blight-Ravaged content.

Frequently Asked Questions

Why can’t I find Blight in the PoE2 Atlas endgame activities list?
As of patch 0.5.2 (June 2026), Blight is not one of the dedicated Atlas mechanics you can force via tablets — those are Breach, Ritual, Delirium, Expedition, and Runes of Aldur. Blight spawns as a random map encounter. Increase your general league mechanic spawn rate via Atlas tree nodes to see it more often.

Should I upgrade towers immediately or build more towers first?
Build more towers first. A T2 tower with Empowering coverage outperforms an unbuffed T4 tower. The minimum viable setup is: stall tower placed, Empowering adjacent, then upgrade the stall tower to T2. Only go beyond T2 once Empowering is in place.

What’s the best tower setup for a lane with a boss spawner?
Stone Gaze (Seismic T4 Path B) is the only tower that hard-stops unique enemies. Place one specifically on the boss lane — the petrify effect freezes bosses in place long enough for your active killing to delete them. Glacial Cage and Temporal slow but do not fully stop boss-tier enemies.

Is Blight worth farming for currency in PoE2?
Yes, for casual sessions. Blighted Maps consistently return oils worth 25-50 chaos equivalent per run in PoE1 benchmarks, and similar returns translate to PoE2 given comparable oil demand for amulet anointing. It is not the highest-ceiling mechanic (that’s Breach or Delirium stacking) but it requires no special investment beyond map selection and basic tower knowledge. High-tier oils for amulet anointing command significant premiums in trade — Golden and Silver oils in particular [2][5].

For the full picture on how Blight fits into your endgame plan, start with the PoE2 beginner’s guide if you’re new, or jump straight to the Atlas progression guide to understand which mechanics pair well with Blight in a single farming strategy.

Sources

1. Best Blight Farming Maps in Path of Exile 3.24 — mmoso.com
2. Blight League Mechanic Guide — outof.games
3. Path of Exile 3.8 Blight Tower Defence Mechanics & Strategy Guide — goldkk.com
4. A Short Guide to Path of Exile’s Blight League’s Tower Defense — keengamer.com
5. Blight Farming Guide — Maxroll.gg
6. Blight League Guide: Mechanics and Strategies — PoE Vault

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.