Undead Siege: Complete Guide

🗓 Updated: 2026-10-12

Undead Siege is the alliance defense event: your whole alliance stands against waves of infected, with heroes on the wall doing the fighting. Two rules define it before anything else: shields do not work, and it is not a points event — the goal is to defend as many waves as possible.

This guide covers how sieges unlock, the difficulty ladder, the hidden multi-squad mechanic that wipes underprepared alliances, rewards, and the top seven mistakes.

How a Siege Unlocks

Sieges are not on a timer — your alliance triggers them (the event becomes available to Alliances 2 weeks after server launch — July 9, 2026 update):

1. Fill the 300,000 Clue Points bar.
2. An R4 or R5 finds the hidden Death Prison on the map.
3. That leader starts the siege and chooses the difficulty.
4. The siege begins roughly 4 hours after the click — use that gap to get every member’s heroes on the wall.

Clue points come from normal daily play:

• Attacking Rebels and the Blight Legion
• Killing Wandering Blights
• Gathering resources on tiles
• Helping allies (help-build and help-research taps)
• Running Alliance Excavation
• Completing Falcon Quests

An active alliance fills the bar through ordinary play; the bar is not the bottleneck, readiness is.

Difficulty Levels

The ladder scales continuously from 2.4M Enemy Might at Level 1 up to 24.5M at Level 10, with territory requirements rising from 13 to 27. Higher difficulty levels also unlock Enemy Mutations — preview the mutations before committing to a difficulty, because a mutation that counters your defense comp is worth millions of Enemy Might.

The Hidden Multi-Squad Mechanic

This is the part of the event the difficulty screen does not tell you, and it is the difference between surviving 20 waves and collapsing at 17:

• The siege sends 2 or more squads at the stated might. Stated 8M means you fight two squads of 8M — effectively double the number on the button.
• At wave 17 of an 8M difficulty, the actual strength is roughly 7.3M x 2.
• At difficulty 6 and above, waves send 3 squads.
• Squad HP persists between waves. Your tank starts the next fight at whatever HP it ended the last one — and your squad 1 must survive back-to-back fights with no heal in between.

A 9.5M player died at wave 17 of an 8M difficulty — worn down by consecutive fights with persistent HP. The stated might is not the fight.

Rewards

Personal Milestones

Each player faces 20 solo waves, with milestones at waves 1, 4, 8, 10, 13, 16 and 20 — tokens, upgrades and chests. If your city falls it will not be attacked again, but your personal rewards stop there: dying at wave 12 of 20 forfeits every milestone after it.

Alliance Milestones

Two rules around the alliance total:

• Membership over 48 hours is required to receive alliance rewards — new joins don’t collect.
• Reinforcing other members doesn’t double your personal rewards — it raises the alliance total. Do it anyway: the alliance milestones are the big payout.

The all-time record stands at 1,193 waves in a single siege.

Deployment: Squads and Reinforcing

• Your strongest squad goes on your own wall. That squad carries your 20 personal waves.
• The rest of your squads reinforce other members — reinforcing raises the alliance total, which is where the shared rewards live.
• Reinforcements land at the member’s wall and fight the incoming waves with them — send them before the waves hit, not after the notification.

The Top 7 Mistakes

1. Heroes not on the wall — the biggest killer. Heroes on the wall are the event; a wall with no heroes is a city waiting to fall.
2. Ignoring wall defense — there is no auto-defend in this event. Whatever you preset is what fights.
3. Starting without 100% clue completion — a rushed start wastes the 4-hour warning window.
4. Underestimating mutations — always read the mutation preview before choosing the difficulty.
5. Not reinforcing members — the alliance milestones need bodies on every wall, not just your own.
6. Starting with partial squads — a half-empty wall squad is a dead wall squad.
7. Logging off without preset defense — offline defense works, but only if it was pre-set. Set it, then sleep.

Run the event with those seven fixed and your alliance defends near its ceiling. Hero setup for the wall and squad composition are covered in the Heroes guide.

📊 Score & Reward Tables

Verified values from game client data (v1.0.87), source: wiki-last-asylum.com. Base values shown without Academy or event research bonuses.

Source: wiki — city-siege

Last Asylum: Plague Wiki

Undead Siege Field Notes: Clues, 20 Waves and Overseers

The siege is an alliance exam in organization, not a one-strong-player event: Falcon quests fill the bar, the wall squad holds, online members heal, strong players reinforce the weak. Launched blind, half the alliance burns mid-way and the chat fills with “why didn’t the shield work” and “who pressed start”.

Clues come from Falcon quests

The alliance needs clues to fill the launch bar, and they come from Falcon quests — above all kill quests against estates, Wandering Blights and the Blight Legion, worth about 300 fragments each. If members ignore those quests, the siege sits half-built.

The tension: many players hoard Falcon quests for Alliance Duel (Sunday/Tuesday/Thursday stacking). That’s fine normally, but when the alliance needs clues, the needed kill quests should be run and claimed daily. Officers should name the targets explicitly — estates, wandering blight, blight legion — not just “do Falcon”.

Who launches and when

At 100% clues, R4/R5 launch and pick time plus difficulty. Never launch because “I’m online now” — half the alliance will be offline, walls unset, reinforcements unsent. Schedule for peak evening online, warn in chat plus Telegram/Discord, and run a 5-minute check: who is online, who is weak and needs reinforcements, who can send 2nd/3rd squads, who has the main march on the wall, what difficulty the roster can actually hold.

Entry gates: Sanctuary level (about 14 on difficulty 1 up to ~27 on difficulty 10), 48+ hours in the alliance (no last-minute jumps for rewards), and no 72h+ offline staleness. Review the roster before launch — newcomers and sleepers don’t help a 20-wave event.

Difficulties, waves and the 20-player rule

Difficulties unlock sequentially — no jumping to 10. Total alliance waves for max rewards scale from roughly 300 on difficulty 1 to ~1,200 on difficulty 10. To step up, at least 20 members must clear all 20 waves — not one top, not five tops. Abandoned weak players who die on wave 8–10 can block the whole alliance, so reinforcing mid players beats admiring top power.

Personal rewards scale with waves survived — all 20 for the max. If a wave burns you, participation ends at that wave’s tier with no re-entry. Pre-start checklist: strongest march on the wall, enough troops, healing ready with resources and speedups, online at start, reinforcement requested early if weak. Most failures are the obvious things: wrong march, empty wall, shield hope, a “5-minute” AFK into smoke.

Shield does nothing, wall does everything

Shields do not stop siege waves. Once launched, waves come regardless. The wall must hold a real squad: strongest defensive or main combat march — good tank, carry, support — never a gather march or a “will swap later” placeholder. Weak players should ask for help early; a timely “I need reinforcement” helps the alliance, silence plus a mid-event wipe doesn’t.

Strong players reinforce the weak with 2nd and 3rd squads while keeping the main march home. A weak city isn’t lazy, it’s just weaker — with help it survives more waves, earns more personal rewards, and adds alliance waves. Assign helpers before start; mid-wave chaos (healing, chat, misclicks) makes late help late.

Healing, cooldown and overseers

Killed troops land in the infirmary — stay online, heal between waves, refresh help when allies take damage. Check before start: healing resources, speedups, free infirmary space, willingness to sit through the waves. A full infirmary plus no resources turns the event into scenery.

After all waves comes about a 2-day cooldown, but clues can be farmed during it — keep running Falcon quests so the next difficulty launches faster. Cycle: gather, launch, 20 waves, rewards, cooldown, gather again.

On difficulties 9 and 10, every 4th wave has a 20% chance to become an Overseer with bonus rewards, and the Overseer has a 30% chance to turn into an Enraged Overseer with better loot. Don’t chase them early: if the alliance barely holds normal waves, heroics cost the stable rewards first.

Pick difficulty by evidence, not pride: how many cleared 20/20, who died early, who needed help, whether healing lasted, whether max waves closed, whether chat panicked. A confident clear moves up; a borderline clear stays. For officers: announce early, assign weak→strong pairs, keep difficulty honest, and explain to newcomers that shields don’t save and the wall march is manual.

Source: Last Asylum: Plague - гайд по событию Осада нежити. Как пройти 20 волн, не сгореть и помочь альянсу by Гейм-Знаток on DTF.

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