Illusioner

Illusioners are unused spell-casting illager mobs equipped with bows.

Spawning
Illusioners have no spawn egg in the creative inventory. It can only be spawned using the command.

Unlike other illagers, illusioners do not spawn in woodland mansions, nor, like the unused giant mob, do they naturally spawn in any biome.

Drops
When killed by a player, any naturally spawned equipment (including their bow) has an 8.5% (9.5% with Looting I, 10.5% with Looting II and 11.5% with Looting III) chance of dropping and will drop with a random durability.
 * 1 Illager Banner.png illager banner, if it is a leader. It is going to always drop the banner when defeated.

Behavior
Illusioners will attack players, villagers, iron golems, and wandering traders within about 12 blocks. It will attack with its spells, and with its bow. It is the only illager that can see its target through walls. An illusioner will always try to maintain a consistent distance between itself and the player. They will quickly back off if the player gets too close.

The illusioner has two spells: a spell that blinds its opponent, and a spell that summons duplicates and makes the illusioner invisible.

Casting blindness
The blindness spell will only be cast if the regional difficulty is greater than 2.

Upon first engaging a new opponent, an illusioner casts a effect that lasts for 20 seconds. It signals this attack by raising its arms, making a strange horn-like sound, and producing black smoke. The illusioner will not cast this spell more than once on the same 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 will cast an effect on itself that lasts 60 seconds, and will refresh the effect whenever the Invisibility's time runs out. It signals this spell by raising its arms, making a strange high pitched sound, and producing blue smoke.

When an illusioner becomes invisible – through this or any other method – it creates four false duplicates of itself. These hover and waver at short distances from the actual invisible illusioner, though they will not really space themselves out until the first time the illusioner is ever attacked. These duplicates face in exactly the same direction as the illusioner, and move somewhat in step with the original, sometimes appearing to no-clip through walls, ceilings, and floors. They will use the shooting animation whenever the original uses its bow, though only the real illusioner can shoot and be damaged.

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, signaling the hit.

If an invisible illusioner receives the effect, all of the duplicates will glow, while the true illusioner will remain invisible.

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.

Data values
Illusioners have entity data associated with them that contain various properties of the mob.

Trivia

 * Illusioners can't attack when any non-bow item is in its hand (using commands).
 * Illusioners hold bows in a different direction compared to skeletons (diagonally).
 * Illusioners can't use tipped arrows that are in its offhand slot (using commands).

Gallery
Illusionist Illusionniste イリュージョナー Illusionist Iluzjoner Ilusionista Иллюзор อิลลูชันเนอร์ 幻术师