Patrol

Illager patrols are common naturally spawning groups of pillagers and vindicators that attack villages.

Java Edition
Illager patrols spawn as a group of pillagers and vindicators, totaling five all together. One of the pillagers or vindicators will be the illager captain. The illager captain wears an illager banner on its head. The other pillagers or vindicators will follow the leader and then target the village.

Bedrock Edition
Illager patrol spawn as group of 2–5 illagers. On Easy and Normal difficulties, only pillagers will spawn, with one of the pillagers being the captain. On Hard difficulty, 80% of the illagers will be pillagers, while 20% of them will be vindicators. One of the vindicators or pillagers will be the illager captain.

Java Edition
Illager patrols spawn around 200 blocks away from villages in, ,, and  biomes, as well as their variants on sand and grass block, or in snow with a block light level of 0–8 and a sky light level of 10–15. Illager patrols spawn naturally throughout the day or night after 5 in-game days. The illager patrols need to spawn in the right biome near a village, regardless if the village is mostly generated in an unusual place. (For example, if a village generates mostly in a dark forest but a portion is still in the plains biome, then the patrol will only spawn in the plains area near the village.) A patrol will only spawn near the village if it has all its doors in place and at least one villager.

Bedrock Edition
Illager patrols spawn around 24–48 blocks away from player in, ,, , , and , biomes, as well as their variants on sand and grass block, podzol, coarse dirt or on snow. Although villages can generate in snowy tundra, illager patrols cannot spawn there. They can also spawn in giant tree taiga biomes, although villages cannot generate there.

On Easy difficulty, illager patrols can only spawn at light level 0–7 on the surface. On normal and hard difficulty, illager patrol can spawn in any light level. Illager patrols spawn naturally after five in-game days, then after a delay between 5–6 minutes an attempt will be made to spawn an illager patrol (20% chance of success), repeating the delay and spawn attempts as long as the player remains in the same chunk.

Behavior
Illager patrols will circle inwards toward villages and then proceed to attack the village and try to kill villagers and iron golems.

The patrol captain always drops an illager banner upon death.

Bad Omen
Upon killing a patrol captain, the player receives 1 to 3 levels of the effect for 100 minutes, which has no consequences until the player enters a village. Then the effect is removed from the player and a raid spawns nearby after about 5 seconds. The level of the Bad Omen determines the number of waves in the raid.