Raiders are unique enemies that attack settlements at night during Raid Event. They have random appearances and are equipped with armour and weapons based on your progress in the Elder's quest. The number of raiders is determined by the number of settlers in the settlement, and they will slowly increase their damage output if they fail to defeat the settlement.
The settlers scale equally in stats as the raiders throughout the game.
Raids will take place occasionally after dusk. The cooldown on raids is a minimum of 2 hours and starts with a maximum of 3 hours. Each raid increases the maximum by 1 hour, while each settlement boss quest, reduces it by 1 hour (never below 3 hours). Raiders will come from a specific direction, and they will spawn in and prepare for a short time before attacking. You can also see the raiders on the island map, so you will know where to defend.
Warning message about upcoming raid
Raiders will come in waves, each wave will consist of several small groups. The raiders will move towards the centre of the settlement and the houses occupied by the settlers. Settlers usually stay in their rooms at night, but they will come out to fight the raiders as they approach their rooms. When a settler loses approximately half their health, they will retreat to their room to heal.
Raiders attacking the settlement
If there is no other settler to distract the raiders, they will go to the nearest occupied room, break in the door and attack the settler inside until either they or the settler are dead. If a settler is killed, the raiders will move on toward the centre of the settlement attacking any settler they find on their way. The more settlers you have, the more they will try to kill before leaving. If you have less than 7, they will only kill 1. If you have less than 12, they will kill 2; at less than 17, they will kill 3; up to a maximum of 5 killed settlers.
Raider attacks will continue until a message pops up that the raiders are leaving. They will flee to the edge of the zone and disappear, even ones fighting at the time.
If a settler dies during a raid, they do not respawn, but the same type has a very high chance to arrive soon after to be recruited.
Defending Against Raids
Among many techniques, traps can be used in defending against raids, such as a Kill Maze For Raiders.