The Illusioner is a mob first introduced in a 1.12 snapshot on the java edition of Minecraft but was never completed. He was later re-added and retextured in the new Minecraft Dungeons DLC: Creeping Winter. So now, this add-on finally brings him officially into the game. The mob is an illager type and spawns in little campsites in the ice plains biome kind of like how it does in Minecraft dungeons. It will attack you as well as villagers and iron golems by creating cloned versions of itself. Not only that but he has a lot more health than the average pillager making him a mini boss like the elder guardian.
Select version for changelog:
Changelog
Changes
Particles
- Vanish particle has a slight texture change
- Recolored Illusioner Arrow explosion
Mobs
- Added the Illusionist
- Removed Kill Clone entity
- Illusioner/Illusioner Clone animation improvements
- Illusioner Clone is now named Illusioner but still identified as Illusioner Clone
- Illusioner attack rotation has been simplified
- Illusioner switches to range mode when in water
- Retextured and renamed Fireworks Arrow to Illusioner Arrow
- Illusioner Arrow no longer has gravity
- Illusioner Clones will now attack mobs that attack the real Illusioner
Items
- Potion of Illusion now depletes after use
- Potion of Illusion no longer spawn particles
Structures
- Illusion Campsite spawns less frequently
So if it dose get more updates as expected perhaps the Illusioner and illusionist would be programmed to appear in the raids if possible.