Minecraft wiki entry for Development_versions, associated text: Triggered when a player inflicted with Bad Omen enters a village.
Pillagers, vindicators, evokers, witches and illager beasts can appear as part of the raids.
Raid progress bar once a village has been entered is displayed like the ender dragon health bar, decreases on pillager kills.
Shows remaining mobs near the end.
Mobs appear in waves if effect has higher level.
Include witches and evokers on later waves.