Hussar said:
Actually, that's kinda my point. That's not an area ripe for interesting conflict. At least not for me because I don't know how to use these things. I never, ever have. They're inscrutable, which means their goals are ... well... opaque. Which means I have no idea what makes them in conflict with the PC's.
Well, there's been several interesting examples of how to do that already in the thread. But this isn't really a problem with the modrons or the slaadi, it's a problem with any creature like this, from aarakocra to the fey courts to, heck, angels. If no interaction challenge like this is to be included in the MM at all, you're writing off a huge chunk of the fun of the game for some people.
But there's a great example of how to use this kind of NPC group in our current Dark Sun game, too. A town is protected by a Fey lord who deals in secrets. It's creepy and unnerving, tense but not obviously hostile. If you were just to rip off that idea and stick modrons in place of the fey, you might have something like...
Logos
(Encounter) A small town found in the wilderness that is in astonishingly good repair, populated by a scrupulously organized populace, who speak with an odd sort of precision in their language, unwilling to use metaphor or simile. When the PC's stumble onto this village, they are told that it is strictly against the law to be on the streets after "curfew," and are told that this is the time when the "cleaning crew" comes out. If the PC's obey the law, the lightest sleepers are awoken by a strange whilrling, clicking noise on the street outside, and if they look out the window, they see strange geometric shapes -- cubes and spheres and pyramids -- walking down the streets, sweeping, picking up litter, and attending to various buildings, mending them, repairing them. If they break the law, this janitorial crew becomes hostile, until they go indoors, repeating the word "VIOLATION" over and over again. If the party slays this cleaning crew, even in self-defense, the other people in the town become resentful and aggressive, telling the PC's that they've caused the destruction of the village by destroying its protectors. This is born out when, in the next few days, the town comes under attack by orcs (or whatever) and gets left in ruins. No one in the town is really aware of why the creatures defend the village -- and the creatures themselves never interact with anything except to punish it for a violation of the town's laws -- but the creatures have been doing this for generations, and the people are happy to live under the rule of the creatures, in exchange for their protection.
(Adventure) The people of Logos are kept well by their alien peace-keepers, but there is a cost for this: they must strictly adhere to the laws the creatures set down. Once each year, a law-maker visits and updates the laws of the town. This year, there is a group of malcontents who believe that the town should be independent, and they are planning a coup: they believe that if the cleaning crew doesn't get its instructions from the visitor, that the crew will fall to chaos itself, losing their guidance. The PC's fall into this as the visit of the law-maker coincides with their visit of the town, and the malcontents are eager to recruit the outsiders into their plot, while at the same time, the leaders of the city want to hire the party to protect the law-maker. The PC's must determine which side they stand on., and must be prepared to fight desperate revolutionaries, or helpful, draconian authority figures.
Modrons want law and order and understanding and organization. Slaadi want chaos and impulsiveness and entropy and freedom. What they want is hard-coded into what they are. And adventurers are often not the most law-abiding types, but they also don't love destruction quite as much as Slaadi to. The conflict is in how the PC's negotiate between the good these creatures are doing and the harm they wreak, and the PC's own beliefs about how such things should be. Which side the PC's choose on a modron vs. townsfolk adventure may speak volumes about that PC's greater views on the world and society and will certainly provoke interesting in-character conversation weighing the goods and ills of such things.
If you can figure out how to use a fey creature, you can figure out how to use a modron, or a slaadi. Just slightly adjust the goals from "nature" to "law" or "chaos."
I can look at Formians and see the whole assimilation hook and that's pretty easy to work with. I can look at a Chaos Beast and that's pretty easy to work with.
