Dark Events are randomly selected alien operations, which are focused around decreasing the effectiveness of your actions, increasing the alien operations, or simply to put an end to the campaign, ending the game permanently. Each month, along the supply drop from the Council, you will be presented with a screen informing you of the three upcoming events, that will become active in the next few weeks.
The player can (and should) counter the effects of those events, as well as prevent them from happening in the first place. One of the mission types, the Guerilla Ops, is entirely focused around this aspect - completion of each of those missions will allow you to disable one of the Dark Events. You will be routinely informed about those missions, as they are one of the most important activities in the game.
As soon as a Guerilla Ops mission appears, you should leave whatever you were just doing and complete it - otherwise you risk the effects of a Dark Event to become active, and some of those can really skyrocket the difficulty. Some of the Dark Events can be used to decrease the progress of the Avatar Project (more on that can be found in the next chapter of this guide).
A list of all the available Dark Events, and their effects if they become active:
A UFO appears on the world map, which will patrol the nearest area. If the Avenger ship appears in its range, the alien ship will start chasing you, which might end up in grounding the ship, after which a special type of mission will initiate.
ADVENT Midnight Raids
Recruiting with supplies costs 100% more.
The effect lasts for one month.
Guarantees that alien reinforcements will appear during Guerilla Ops missions.
The Aliens find a mole within the Resistance, reducing the Retaliation counter by 2 weeks.
ADVENT Alloy Padding
All ADVENT troops are equipped with additional armor.
Causes the Faceless enemies to appear on your missions. This happens in places in which civilians are present.
Avatar Project: Minor Breakthrough
Increases the progress bar of the AVATAR Project by 1.
ADVENT Rural Checkpoints
Decreases the amount of resources provided by the Council by 50%
All actions using Intel now cost 100% more.
As you can see, all of those events influence the gameplay, which is why you should react to them as quickly as possible by performing the above mentioned Guerilla Ops missions - the more contacts you have, the more often you will be presented with a mission of this kind. If you haven't established contact with resistance on a given continent, you won't be able to take part in the mission they provide you with, unless you make contact with them.
A few things to point out:
- Upcoming Dark Events can be checked by clicking the text on the top of the screen, just below the Project AVATAR progress bar.
- Active events can be reviewed by clicking on the list on the left side of the screen, below the objectives.
- While on the screen showing the upcoming Dark Events, you can check how much time is left for a next Retaliation mission, and how long will it take to construct a new alien facility.