The Cult from Diablo 3

Diablo 3's cultists appear after the defeat of the Skeleton King, and may be the best monster "set" in the game.

The main thing Blizzard did really well with Diablo 3 was the way it constructed "monster sets". Groupings of monsters that are commonly found in an area together, and typically compliment each other well. The best "set" in my opinion is The Cult, and it's totally stealable for table top RPGs.

First, the components of the Cult.

1. Basic Cultist. Nothing fancy. Has a flat topped hood and a dagger, and pretty much charges in swinging their weapon wildly.

2. Summoner. Has a pointy hood. Summons in demons, normally demon dogs. Can shoot small fireballs in a pinch.

3. Vessels. Don't move. Hold a staff with a bell on the top, hit the staff on the ground. Have been impaled with huge spikes in their backs. Die very easily, but if left alone transform into a partial demon (Dark Thrall) with huge claws, fangs and fire and come streaking across the map at you.

4. Demon Dogs. Warped in by Summoners.

5. Dark Berserkers. Large demons with a large weapon. Relatively slow moving, and have a huge showy "wind up punch" type hit. You've got plenty of time to get out of the way of their strike, but if you don't it could kill you in one shot.

6. Dark Thralls. The transformed Vessels.

The best part of the cult is how all these pieces work together.

1. Cultist Warp. A large number of basic cultists can suddenly "warp in" at a location. They all emerge from flaming runic circles on the ground so you get a visual of where they're about to show up and have a split second to try and plan.

2. Summoner Variations. Sometimes you'll get a summoner in with a pack of normal cultists. Normally hanging towards the back, so they'll try and hit you with a few fireballs and then will warp in a demon dog. The demon dog warp in effect is nice, because the dog appears about 20' in front of their location and is attached to the summoner by ropey blood colored magic. I like to imagine that the demon dog is being formed from the very blood and flesh of the summoner, and that's how I'd run it in a game. Next you'll occasionally get a summoner standing in a swirling pool of black energy waving their hands around and clearly summoning. If you can kill them in time, the portal basically collapses. If not, they warp in multiple dogs. Finally you'll get 3 to 5 summoners around a black portal, waving their hands around and summoning dark berserkers.

3. Vessels. Always tucked out of the way in nooks and crannies and grouped up, so you've got to kill lots of them fast, or you're in trouble.

The main things that make this cult so good I believe are:

1. It's very visual. Each creature type is visually distinct. This has more to do with it being an isometric video game I'm sure, but it's a powerful and functional way to present threats in the table top world too.

2. It starts out easy, but ramps up fast, and it shows you that it's ramping up. Again, very visual, but this time, it threatens in an obvious way. The sorcerers are waving their arms and standing in pools of inky black that crackles with unholy lightning. Strange runes appear on the ground before demons and cultist reinforcements appear. The player can view the scene and assess potential threat areas, and then make decisions on how to deal with what might be about to happen. It's also consistent so continued exposure to the cult increases player skill by enabling them to better judge what's happening.

3. The dogs, cultists and brutes swarm to the front. The weak summoners and vessels hang in the back and summon in more shit or shoot fireballs, or prepare to transform. These natural sort of walls form, so even if you know what you need to do, sometimes you can't do it, and need to retreat.