The Illager is a hostile mob added in Update 1.11. They are similar to Villagers, except they have pale skin and dark clothes. They are considered to be Village outcasts. They spawn in Woodland Mansions, and do not respawm after they are killed. There are two variants, the Vindicator and Evoker.
The Vindicator spawns with an Iron Axe in their right hand. They drop 0-1 Emeralds, which can be increased with the Looting Enchantment. If a Vindicator is named Johnny or has the Johnny tag set to 1b, it will be hostile to all mobs aside from Evokers and other Vindicators, whereas normally it will only be hostile to players and Villagers.
The Evoker is a mini-boss. They drop a Totem of Undying and 0-1 emeralds when killed, which can be increased with the Looting Enchantment. They are hostile to players, Villagers, and Iron Golems. It will change the Wool color for any blue Sheep within 16 blocks to red. They summon Vexes and Fangs to attack. The Fangs do 6 damage, regardless of difficulty.