The Cultist is an uncommon monster showing up in Creeplight Ruins, Demonic Library, and various class challenges. They are a very weak enemy and would be excellent targets to exploit for bonus XP, if not for Revives. Cultists, upon death, give no XP at all and spawns a Zombie one level lower than the Cultist originally was. Zombies, being the tough, durable monsters with few weaknesses they are, makes high level cultist kills highly impractical for all but Priest and is a waste of resources, and the reduced level of the zombie means it's worth even less experience than usual.
All things considered, cultists are a nuisance and little else, but they can be used to your advantage nevertheless. The zombies, despite being a level lower, still can contribute to popcorn bowls. Aside from that, Cultists make excellent bloodcows for Life steal, given their low damage and the fact that there's no real reason to ever finish them off unless you need a bit more exp. Lower level cultists, or very high ones, also make for prime IMAWAL targets to make up for the lowered XP value they generally bring to the map. The Cowardly trait coupled with their low damage also makes them fairly easy and cost efficient to move around to serve as an anvil for Knockback damage against more important targets.
It should be noted that Creeplight Ruins has a special subdungeon that always appears, which turns all Cultists on the map into more threatening Shades. This isn't as bad as it sounds, however, since the shades maintain the Cultist's level and don't revive, you get full XP value from them. It's often a good idea to not kill any Cultists in that dungeon until you transform them later, and use the Shades as more valuable popcorn to assist against the boss.
Anoobis is three formed boss of Creeplight Ruins, who is a particularly tough Cultist called Anoobis. Like the standard monster, Anoobis also revives, but twice for a total of three forms.
None of the forms are particularly tough, but a hybrid of physical and magical damage will have the easiest time. Only the final form awards XP. It's recommended to fight each form one at a time, making sure to recharge between each with either a level up or remaining blackspace, as Anoobis can only regen to the top of his current form. Trying to do all three as if he were one singular monster makes the fight significantly tougher.
Note: Anoobis provides no experience or gold when killed in his first and second form.