The Maguana Mace menaces with spikes of iron.
Just recently, someone asked on RogueTemple for enemy names and types. I wasn't able to contribute a lot, but tried to outline how my creative process usually works when I try to come up with cool enemy types. I tend to get weird ideas at the most impossible hours of the day, mostly after obsessing about some weird stuff I've read or seen. Good SciFi is helpful (lots of weird aliens), but I've had great ideas from reading biology articles, too.
I ended the post I wrote in response of said roguetemplar with a short collection of ideas I'd come up with on the fly. Someone had mentioned magma-dwelling salamanders and creatures looking like rocks, and I just threw some stuff together that might fit the theme, to show how easy it is to come up with at least partly original stuff once you have a basic idea to work from.
I've included my full post here; if you don't care for creating interesting enemy types feel free to skip it.
Honestly, I'm not very interested in just enemy races. Yeah, it's cool to think up new races, or put interesting spins on classic races (like ToME4's elves), but that's only good for providing a general stereotype. Creatures (and that includes people) are forged by their environments and life styles. So, thinking about the big picture can give you much cooler ideas.
What you want to think about, for example, are the actual types of enemies within those races. How is their society structured? For example, if they're eusocial, you're most likely to encounter workers and soldiers, and one or more queens, perhaps also drones. What kinds of different warriors/professions do they have? How are they likely to interact? All things that could inspire the actual enemy you'd encounter. What kind of civilization are they, while we're at it? What are they good at, how do they live, do they have any mythical beliefs?
Also interesting are the actual ecosystems within your dungeon. This is mostly important when you have uncivilized creatures. There's always a food chain, and you know that you can use that to come up with cool ideas. Blarghs might be a cool monster, but if they're small, odds are that there's a Blurgh around that eats them. And because of that, Blarghs are never without Blirghs that keep an eye out for those horrible monsters. You're probably already imagining what all of those could look like. Real-world inspiration can help a lot here, or just lots of reading good sci-fi.
Thinking about these things tends to help me a lot. Just think about an environment, some creature you'd like to have there, and work from there with inspirations in nature and fantasy/sci-fi.
With that said, let me pull something out of thin air for you. Just for demonstration.
So yeah, there might be salamanders that live in lava. What do they eat? You can hand-wave that one away without too much trouble. It's probably too small for you to fight. What eats them? Oh boy, the evil magma squids, of course! Who else? So, who are these guys? I myself imagine them like vampire squids. They wait in the magma pools for unsuspecting salamanders, camouflaged as rocks using their stone-colored skin. How do they fight? Some magma squids (I'm calling them calamagmary, from Latin calamarium) use their prehensile tentacles to quickly catch the salamanders. A second type, let's say those are the male magma squids, shoot with super-heated magma like ink to fry the salamanders. They might also want to fry unsuspecting adventurers wandering too close to their pools. So are they the top predators in the magma sea? Hmm. let's just assume there's something bigger. Very much bigger. Let's call it a Magmasaurus Rex, an ancient fire dragon dinosaur godzilla thing. (which is totally not a ripoff Volvagia with legs, heh.) And it lives at the bottom of the magma sea, coming up only to catch whatever it finds. If you're a big frakking dragon, you can kill almost everything in your vicinity and eat it, too. Boss fight right there.
But wait! What if there are intelligent, civilized beings down there? Who would fit into the environment? There's probably a cool idea in the back of my brain right there, something to do with lizard folk. Let's call them Maguanas (a portmanteau of magma and iguana... yes, my names suck ). Lizards like it warm, so a hot, magma-lake-filled environment should be just right for them. They're a rather simple people with a preference for mining and forging. They will have soldiers equipped with heavy armor and large weapons. Because I feel like it, I'm going to give them lots of spiked maces and spiky armor. Iguanas are kind of spiky, so that fits. They may have tons of spiky things in their small towns carven into the solid rock.
What kinds of guys could they have in their society? Well, let's keep it to warrior folks, okay? I don't feel like butchering Maguana babies. Let's give them their soldiers and scouts, with heavier and lighter equipment respectively. Because they're a tribal culture, they will have chieftains. These are probably battle-hardened warriors, not easy to kill and with really good loot.
Of course, the Maguanas should worship the big Magmasaurus, right? They're probably going to have priests dedicated to it. And because we're in a fantasy universe, priests have magical powers. So we'll see Flame Acolytes, Magma Priests and the powerful Ashen Archpriest. They're probably going to sacrifice things to the Magmasaurus. Living things? Hah! Save the poor <Insert Player Race Here> sacrifice from its death at the hands of the Magmasaurus, and learn of the forbidden Fire Temple he/she has found in the depths, or partake in the ritual, gaining the Maguana's trust and support. Will they teach you their secrets of magma magic? Will they allow you into the Lava Library, where the mystical secrets of their ancestors are carven into the cavern walls? Plot twist right there.
I could go on and on, but I think this is enough for now. To think up a fantasy race is to imagine the world it was born in, what influenced them, why they are the way they are. A lot more fun than just "Yeah, wooden elves, whatevers." The plot writes itself as you pull ideas out of your head and build the world of your dreams. You'll still have to do the thinking, but it's so much fun.