Threat (Long War)

The Aliens adjust their strategic operations based on how threatening they perceive XCOM to be. Threat determines which kinds of missions the aliens will run each month & the likelihood that a particular landed UFO will be a trap.

Threat Counter

A running tally of threat is incremented over the course of the month as XCOM successfully launches operations against alien UFOs.

• Shoot down or successfully assault a Scout, Fighter, Raider, Destroyer, or Abductor: +1
• Shoot down or successfully assault a Harvester, Terror Ship, Transport, Battleship, Assault Carrier, or Overseer: +2

This threat counter is used to determine the threat category in the following month as well as the likelihood that a particular landed UFO will be a Trap UFO in the current month.

Trap UFOs

The chance of any particular landed UFO being a Trap is based on the current threat counter:

• Chance of Trap: Threat Counter / 30

Threat Category Level

The Threat Category Level at the end of a month determines the types of missions the aliens will field in the next month and also the amount of threat to start with at the beginning of the month. Threat Category is derived from the total threat generated in the previous month, with one exception: if an Alien Base was raided in the last month, the Threat Category is automatically set to 4.

• Threat Category Level: Threat / 2 (rounded down and capped between 0 and 4)

XCOM starts each month with a minimum amount of threat, derived from their Threat Category from last month.

• Monthly Starting Threat: last months Threat Category Level - 2, minimum 0

The chance that the aliens will reroll the location of a Harvest mission if it resides in XCOM territory (i.e. has a satellite over it) is proportional to the current months threat category.

• Reroll chance: Threat Category Level / 10 (up to 40% at threat category 4)

This reduces Alien Resources by 5. The reroll algorithm will always pick a random new location without a satellite.