Illager

An illager is a type of hostile mob that regularly spawns in woodland mansions, patrols, raids, and pillager outposts. All illagers are hostile toward players, villagers (excluding baby villagers), wandering traders and iron golems.

Classification
There are four specific criteria for a mob to be considered an illager:
 * "Johnny" vindicators do not attack the mob.
 * The mob cannot be damaged by evoker fangs or a ravager's roar.
 * The mob does not fight back when hit by a missed arrow shot by a pillager or illusioner.
 * The mob does attack villagers but ignores baby villagers, unlike zombie variants.

Ravager jockeys
A ravager jockey is an illager that spawns riding a ravager. The riders can be pillagers, vindicators, or evokers.

A ravager ridden by a pillager spawns at raids in Wave 5. Ravagers ridden by vindicators and evokers spawn at Wave 7.
 * Java Edition

A ravager ridden by pillager spawns at raids in Wave 5 and 7. Ravagers ridden by evokers also spawn at Wave 7. The ravagers ridden by vindicators do not spawn in raids, but can be spawned only with commands.
 * Bedrock Edition

Occurrences
Illagers spawn naturally in patrols and raids. They always spawn naturally in groups while in patrols and raids, or inside their structures.

Only the pillager, vindicator, and evoker spawn naturally.

Vindicators and evokers that spawn naturally in woodland mansions do not despawn or respawn.

Ravagers spawn exclusively in raids.

Raid Captain
Illagers sometimes have their own captain. Any illager has a small chance to be a raid captain with an (even when using a spawn egg, or when summoned by commands). Raid captains can spawn in raids and patrols.

$$, the ominous banner equips on the illager's helmet slot. $$, the illager banner equips on the illager's chestplate slot.

Event
Illagers have their own in-game events, led by raid captains:
 * Patrol &mdash; a naturally spawned group of five pillagers roaming the landscape and monitoring the villages.
 * Raid &mdash; waves of illagers and witches spawn and attack a village with ominous horn blares. $$, An illager captain spawns in each wave with other illagers, usually with a vindicator as the captain. It is triggered when a player with the status effect enters a village. Raiders and villagers usually have different behavior in a raid. In Bedrock Edition, any killed raiders drops special loot. Both raiders and villagers celebrate after defeating or saving a village respectively.

Effects
Killing a raid captain in patrols, in a mansion, or in an outpost inflicts the player with the effect, which triggers a raid when that player enters a village with the effect still active. When all waves have been finished in a raid, the effect is given, which decreases prices when trading with villagers.

Rune
Illagers have an alphabet called, a rune font from Minecraft Dungeons. Currently usable only via commands.

Java Edition
All illagers ignore baby villagers, but may still hit them by accident.

Illagers do not retaliate when hit by a missed arrow shot by a pillager or illusioner.

A vindicator can disable the player's shield with its iron axe attack, even when riding a mob. If a player fails to land a melee attack on a vindicator that rides a ravager during a raid in Hard difficulty, the vindicator rider can deal great damage to a player without protection from a shield.

All illagers, ravagers, and witches within 48 blocks of a bell that has been rung gain three seconds of the effect, effectively highlighting them through walls.

For unknown reasons, ravagers aren't illager in game.

Reinforcements
On all difficulty levels, damaged illager mobs call all other same type illagers within an area centered on the attacked illager to target the attacker, as long as the attacker is a non-illager. For example, pillagers attack a skeleton that injures another pillager, but pillagers do not aid a vindicator hit by a skeleton.

Raids
During raids, vindicators can open doors like villagers. They can break wooden doors in normal or hard difficulty, if they cannot open the door successfully. Evokers and illusioners gain high movement speed without any effect.

A raid captain spawns in each wave with other raiders, usually with a vindicator as the captain.

Illagers pick up ominous banners dropped by raid captains, depends on how many raid captains die in this wave. If the raid captain is still alive, they do not pick up the banner from last wave remains or if thrown by the player.

Patrol
All illagers, ravagers, and witches joins nearby patrol actively. If a "Johnny" vindicator joins a patrol, all patrol members assume the "Johnny" vindicator's aggressive behavior.

Bedrock Edition
Vindicators and evokers do not despawn and are passive on Peaceful difficulty.

All illagers and vexes ignore baby villagers, but pillagers and illusioners may still shoot them by accident.

A dispenser can equip an evoker, vindicator, pillager with armor. However, No armor are visible on them and no armor drops upon death.

Pillagers and ravagers do not purposefully attack other illagers. However, non-pillagers and non-ravagers do attack pillagers who hit them with missed arrows. Vindicators and evokers retaliate against a pillager if the pillager accidentally hits the vindicator or evoker with an arrow, although the evoker fang deals no damage to pillagers. Vexes summoned by an injured evoker can still attack the pillager.

A "ravager with vindicator rider" is unused $$. It can be summoned by a spawn event command without raid configuration.

After Texture Update, illagers still use the java 1.14 snapshot texture, including some of the marketplace textures (for example, pillager's arms). Also, a ravager's leg texture in Bedrock Edition is different from that in Java edition.

Trivia

 * According to Minecraft Mobestiary, illagers were "expelled" from villages due to their "unspeakable activities". After the release of Minecraft Dungeons, the setting of illagers has been changed and expanded.
 * Witches allied with the illagers during raids. Cory Scheviak jokingly explained that witches spawn in raids are just along for the ride.