Vault raids and defense

Vault raids are nighttime intrusions that test your Vault’s security and defenders. When a warning appears, you have up to two nights to prepare: assign residents to Vault Defense, improve Security where possible, and make sure you are not relying on vulnerable common supplies.

Prepare when a warning appears

The most useful response to a raid warning is to post available residents to Vault Defense. The emergency assignment can take effect that same night, but a resident only helps if they attend it.

Your Vault’s defense combines:

• Perimeter Security from powered infrastructure and defensive upgrades.
• The player’s current Strength, Combat, and Health.
• The Strength, Combat, and Health of every resident who attends Vault Defense.

When the intruder arrives, the game compares your total defense against the attacker’s power. The result can be a clean repulse, costly repulse, breach, or overrun. A successful defense prevents theft.

How warnings work

Raids do not happen the moment their warning appears. The day-end terminal reports signs of an intruder without revealing their identity, objective, power, or exact arrival night.

The intruder can arrive on either of the next two watched nights. Most arrive on the first night; if that night passes without contact, the warning becomes imminent for the final night. Only one intrusion can be pending at a time.

What thieves can take

The current v0.27 raid pool is limited to thieves. They target common supplies, not weapons or progression resources.

Thief	Preferred supplies
Scavenger	Water, then Toxwater
Drifter	Numb Agent, then Dust Rush, then Fury Shot
Courier	Stitch Kits, then Credits, then Scrap Metal

Thieves can take Credits, Water, Toxwater, Scrap Metal, Stitch Kits, Dust Rush, Fury Shot, or Numb Agent. They cannot take weapons, Circuit Boards, Breach Charges, Water Filter Parts, or Training Gear Kits.

The amount a thief can carry starts small and grows as the campaign continues. If their preferred supplies are unavailable, they can take another eligible common resource instead. An intrusion can resolve without a loss if there is nothing eligible to steal.

After the raid

Repelling a thief protects your stores. If the player joined the defense, they receive Combat Effort +10; each attending Vault Defense worker gains +1 Combat. A successful theft grants no Combat progress.

After any thief attack, Raid Pressure drops by 8. New Raid Pressure changes and intrusion rolls pause for two days. The day-end terminal records what happened, including stolen resources or the defenders who helped repel the thief.

How raid risk works

Exposure represents how much hostile attention your Vault attracts. Residents, restored electricity, an operational purifier, exposed infrastructure, and temporary raid effects can all add Exposure.

Exposure changes Raid Pressure once per day. Raid Pressure is a risk indicator, not a countdown: reaching 100 does not guarantee an attack.

Exposure	Daily Raid Pressure change
0	-2
1 to 9	-1
10 to 14	No change
15 or more	floor(Exposure / 10)

The Central Atrium’s Operational Hub unlocks Vault Status, where you can check Exposure, Security, Raid Pressure, the current forecast, and the Vault’s automatic defense outlook.

Raid Pressure	Risk forecast	Daily warning chance
0	Hidden	0%
1 to 24	Unnoticed	2%
25 to 49	Rumors	4%
50 to 74	Watched	7%
75 to 89	Targeted	10%
90 to 100	Priority Target	15%

Current alpha limits

Natural raids in v0.27 are limited to the Thief tier. They do not damage the player or residents, cause escapes, or award salvage. Medical Duty, stronger attacker groups, injuries, deaths, and other raid effects are planned for later development rather than the current natural raid pool.

Exact values may change while the game is in alpha.

Related topics

• Vault management
• Combat system
• Time and calendar
• Development roadmap

Download the current public build on itch.io, follow v0.27 development on Patreon, or join the community on Discord.