The Solastians (Bird-like humanoids)

[Enthods]

Imagine a creature who stands six to seven feet tall, whose great large eyes watch your movement keenly. The large wings stretching ten feet or more unfold from their natural position behind the large chest. Great colors ranging from jet black to pure white with secondary colors from red to greens. Their four fingers point like talons, their three claws stretch to balance the creature. They wear little clothes but for golden and silver armors and fine thin silks.
Sound intrigued by this creature? I hope so. I really think Ancient Egyptian gods are cool and this is based on Ra. I just have one question. These creatures would be unstoppable in my opinion, they are not barred by mountains, walls, or anything else. They can deal deadly strikes against their enemies yet they aren't the key part of my world, if anything they are a small portion. Desert dwellers with great city-states. So what would keep them from conquering the world? My first thoughts were natural inability, their hollow bones pose them as week against say a human. Another thought was politically they are introverts. This is all I have come up with to keep them contained yet I know there is something else that would put them on the weaker side of the world.

 

[CupofJoe]

They sound cool.
Can they fly? Do they use weapons?
If they wear armour and fly? One is going to compromise the other. Distance, speed, protection, something would have to suffer.
Birds are proportionally at least as strong as humans [stronger I think] and usually much faster to react.
Their bones wouldn't be weaker but they would be lighter. Any flying creature is vulnerable to broken bones. Once they can't fly it is usually an easy target.
If you need to limit them, something simple like a slow breeding cycle could make sense.
One egg every two or three years, and the young Solastian having to grow up and mature for a dozen years before they can mate...
I you want a counter to them... I have the other side have very good archers or anything that would look like anti-aircraft defences.

 

[Ban]

Psychological differences. These creatures might be capable of building cities but that doesn't mean that they think like us humans. These solastians might simply lack the desire to control vast amounts of land. Perhaps they are a more conservative thinking species, who see more value in their traditions in the desert than anywhere else. Perhaps they can't fathom the thought of not living in their known environment, they lack the creativity for it.

Both dolphins and chimpanzees know how a mirror works but their behaviou, physiology and brains work differently. Same thing can apply to your species compared to humans.

 

[indonesiancat]

If flying humanoids exist, other humanoids who can't fly will create ways to counter them. For instance building domes to cover the cities from aerial assaults, or just different forms of weaponry that are unusually effective against the birdpeople.

It could also be that these birdpeople are peaceful, working more with science and philosophy rather than the squabblings of the other species.

 

[trentonian7]

Just to echo the comments above, it's unlikely another species would think exactly the way that humans do. Not all animals care for aggressive expansion of their territories and perhaps your bird race is the same way; why leave the desert? I agree a lower population would work; perhaps there's a recessive gene causing infertility or maybe a higher infant morality rate. Also, though a bird's bones are not weaker, they are lighter and this is to enable flight; if your birds are wearing armor, it's unlikely they could fly at least with any of the same ability. Perhaps in any conflicts, they fight without armor. They still have the very profound aerial advantage, however, they are much more susceptible to injury from ranged weapons and melee on the ground. I imagine other races would be able to counter by wearing armor, training bowmen, and even developing rotating ballistae or other anti- aircraft type weapons, assuming your world's technology permits it.

 

[K.S. Crooks]

What may limit their ability to conquer the world first is their physical capabilities. They may be able to fly but perhaps not a far distance so oceans and deserts pose a great obstacle. They may only be able to withstand a narrow range of temperatures, which limits where they can go. They may be able to fly, yet they may not have any way to do the same for their machinery, caravan, etc. that needs to be transported to mount an expedition or invasion. They may have legends/myth/religions that scare them from exploring the rest of the world. If they are isolationists and humans don't know of their existence they may be trying to keep it that way, especially if their population is vastly out numbered by humans. This situation is similar in context to different stories that have Atlantis still existing in our world and the reasons why they don't try to take over the world.
Hope this sparks few ideas.

 

[Caged Maiden]

If you want some ideas for why they haven't taken over the world, look at Corax in the White Wolf game, Werewolf. Cora can assume the form of what you're talking about and it's pretty clear about their limitations.

I love the idea, but I also agree that a psychological difference is maybe the best way to go. Someone once asked me why my werewolves didn't take over the world, and I said simply, they didn't want to. Maybe they could have slaughtered people in the thousands before anyone developed a strategy against them, but they were secretive people who weren't murderers. They want to be normal and fit in, not rip throats out with their teeth. Of course, when threatened, the react violently with their natural abilities, but they still have no desire to take over.

Best wishes. I hope the book helps.