Hussar
Legend
I'm still not sure what either kind is good for. What kind of adventures would I use them in? What's their role? I get Inevitables. They will be encountered as they go after people and for good reason. Where are modrons encountered? I understand the alien infestation angle they were talking about. What other use is there for slaads?
This. A Thousand times this. What is the point of having creatures in the game that are pretty much just so much background?
Stop trying to create world building engines out of the Monster Manual.