Hey, lab, I was wondering if you guys could help me out. I need help with monsters and beasties for my RPG, Legion: Hell on Earth. But I need more enemies for my PCs to fight. I mean, I've got demons, but they should really be more like boss-type enemies, the big, bad demons anyways.
But I don't want to fall into the "orc" problem, where all my players ever fight are "grunt"-type demons. I've got werewolves and vampires, and Hell-allied humans, but I certainly need more. Any suggestions would be great.

Different Cultures
Have a look at other religions and myths from around the world. You could adapt Japanese oni, kami or tengu as demons. Or, how about Hindu gods translated into demonic adversaries.
Another option, look at old fashioned monsters and urban myths. Maybe big foot was a type of demon who escaped hell. Other possibilities are the Loch Ness Monster, the Jersey Devil or even the obscure Red Caps.
Hope that helps!
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