Illusioner

The illusioner is an unused illager armed with a bow. It attacks using illusions and can also fire arrows.

Spawning
An illusioner has no spawn egg in the creative mode inventory. This way, an illusioner can be spawned only using data packs or the in-game command. Illusioners do not spawn in woodland mansions or pillager outposts structures nor at raids or patrols events. Similar to the others unused giant and zombie horse mobs, illusioners do not spawn in any biome, monster spawner or world-generated structure.

Drops
When an illusioner is killed by a player or a tamed wolf, any naturally spawned equipment, including its unenchanted bow, has an 8.5% chance of dropping (or 9.5% with Looting I, 10.5% with Looting II and 11.5% with Looting III) and drops with a random item durability. In addition, experience orbs are dropped on player or tamed wolf kills. The illusioner also drops one illager ominous banner if it is a raid captain.

Behavior
Although they do not naturally spawn in raids, illusioners spawned by the player attack players, adult villagers, iron golems and wandering traders within a 16*4*16 cubic area.

An illusioner joins a nearby raid if it occurs or joins a patrol if sufficiently near a patrol captain.

The illusioner attacks with its spells and its bow, firing an arrow every second. Unless the illusioner is summoned using commands, it cannot attack with a non-bow item in its hand, cannot use tipped arrows in its offhand slot (but can use spectral arrows) and cannot use enchanted bows. Also, it is the only illager that can see its target through walls.

The Illusioner moves quickly on a semi-circular fashion and always tries to maintain a consistent distance between itself and the player, strafing from left to right and vice-versa, retreating if the player gets too close or advancing if the player retreats.

Finally, the illusioner has two spells: a spell that blinds its opponent and a spell that summons visual pseudo-duplicates and makes the illusioner invisible.

Casting blindness
The illusioner casts its blindness spell only if the regional difficulty is greater than 2. As result, the world difficulty setting, the inhabited time of a chunk, the total daytime in the world and the phase of the moon from the day-night cycle affects its ability.

An illusioner casts a effect that lasts for 20 seconds upon first engaging a new player opponent. It signals this attack by raising its arms during a short-timed animation, making a low pitched sound and producing a black mist of particles. Other entities (typically a wolf, a snow golem or an iron golem) do not trigger this magic. The illusioner does not cast this spell more than once on the same player opponent, unless it has first shifted its attention to another opponent and then back to that original opponent.

This spell resets the illusioner's spell cooldown to 1 second and resets the cooldown for the blinding spell to 9 seconds.

Summoning duplicates
As long as an illusioner is engaged in combat, it casts an status effect on itself that lasts 60 seconds and refreshes the effect whenever the Invisibility's time runs out. The illusioner signals this spell by raising its arms, making a strange high pitched sound and producing a blue mist of particles called "mirror".

When an illusioner becomes invisible through this or another method, it creates four false duplicates of itself. These hover and waver at short distances from the actually invisible illusioner, though they do not space themselves out until the first time the illusioner is attacked. They face in exactly the same direction as the illusioner and move somewhat in step with the original, appearing to no-clip through blocks like a vex does. Despite using the shooting animation whenever the original uses its bow, only the real illusioner can shoot and be damaged.

The clones move to new positions if they were not triggered and are still bunched together. The Illusioner can also do this once in a while to "refresh" the clones' positions.

When the real illusioner is damaged, its duplicates all snap back to where the real illusioner is, then quickly snap back out to new positions, making a teleporting sound, signaling the hit.

If an invisible illusioner receives the effect, all of the duplicates glow, while the true illusioner remains invisible. Moreover, only the invisible illusioner burns when catching fire.

The duplicates dissipate once the illusioner's Invisibility effect ends.

This spell resets the illusioner's spell cooldown to 1 second and resets the cooldown for the invisibility spell to 17 seconds.

Sounds
Illusioners use the Hostile Creatures sound category for entity-dependent sound events.

Entity data
Illusioners have entity data associated with them that contain various properties.

Trivia

 * The illusioner displace sound almost is the same as the traditional teleport sound displaced by teleportation via an ender pearl or chorus fruit, endermen or shulkers, albeit with a slight distortion at the end.
 * Illusioners shoot backward when they are in a boat.
 * Illusioners hold bows in a different direction compared to skeletons or players, a little more diagonally.
 * The illusioner's second death sound is the same as the evoker's second death sound.