Ahh the Supernatural solution.
Minor spoilers for Supernatural here (I'm on S10 people so don't spoil me on anything big please), but after a lot of demonic badguys who absolutely fit the over-emotional, untrustworthy idiot mould, Supernatural eventually came up with a demon called Crowley who is smart, reasonably respectful (he likes to take the piss but not when it'll cause him problems), definitely diplomatic, and very insistent about sticking to his deals. He gets a huge amount of play because he's not a zealot, an idiot, a crook (in the normal sense), overemotional, is not really that arrogant/filled with hubris, and so on, where virtually all other demons (and naughty angels and so on) who are those things meet sticky ends in fairly short order. He's a "Crossroads Demon" originally so is entirely about signing and fulfilling contracts (and in one season is directly contrasted with a much more D&D-ish demon). He's even against schemes which might delegitimize the "contract economy" by lowering trust in it among mortals (i.e. he's focused on long-term profit rather than short-term).
Interesting. I never watched
Supernatural myself, my inspiration was primarily
The Screwtape Letters, though a few other bits and pieces are in there (some Tim Curry influence I'm pretty sure, and references to Dante's
Inferno.) And yes, Al-Ikhino would absolutely try to shut down someone who might undermine the confidence in devils dealing fairly with their clients. That could be an interesting future event, now that I think about it. Will keep that in my back pocket for times when the adventure loses its path.
I feel like dragons that don't reek of overweening greed, arrogance and hubris aren't really dragons, myself, which I think is part of the issue. They're literally supposed to be exemplars for those things. If they're all careful planning, what's even the difference from a Wizard who knows Shapechange (a question posited by more than one fantasy novel, I note)?
Well, in my setting, dragons are technically a different class of being compared to ordinary mortals. There are three overall such classes. The first is mortals, which you already know well: humans, elves, dwarves, orcs, dragonborn, tieflings, etc., not much new there. The second has been called "Servants," which is more or less "outsiders," though only from the perspective of natives to the world the PCs come from. Devils and demons are "fallen" Servants, and the Safiqi priesthood claims that all Servants were created directly by the One (their monotheistic deity) to administer and nurture creation. I have endeavored to keep this an open question: it is not possible to prove that the One is what They claim to be, and no magic can unequivocally answer the question. There are alternate beliefs and those beliefs have merit without being strictly superior.
The third and final category is Guardians. Guardians are chosen by powerful forces (such as the great spirits of the Spirit World or the Servants) to directly attend to the land and to guide and oversee the everyday lives of mortals. Genies and dragons are two known types of Guardians, but genies have almost entirely abandoned their covenant, leaving the mortal world behind to go to Al-Akirah, the elemental otherworld, where their powers are enhanced. As a result of abandoning but not ending their covenant, their powers no longer work as they should, and very very old "noble" genies for some reason retire from public life and no longer engage with politics or even magic, the exact reason for this has not been discovered.
Dragons, on the other hand, have preserved their covenant and act as advisors and protectors, but never as overlords...unless they turn to evil. The aforementioned black dragon is one that turned evil long ago, and was almost destroyed by Tenryu Shen, a gold dragon who had formerly been the black dragon's extremely close friend (as close as siblings.) Said black dragon escaped and has come to Al-Rakkah, a city in a land that has no preparation and no defenses against draconic incursion. The dragon has had to work their way up from nothing, taking two centuries to do so, and is closing in on true control. Some of the impulse to rule is, in fact, an effect of still having the covenant which gives all dragons near immortality and prodigious magical power, amongst other things.
I have expressed some of the difference between mortals and these other two types of being as one of higher dimensionality: Servants (celestials and fiends) are genuinely higher-dimensional life forms "compressed" into only three dimensions when they interact with the mortal world, while Guardians are beings that were originally mortals (thus three-dimensional) but which have become partially higher-dimensional as a result of their covenant with whatever great power they assist.
In theory, a powerful Waziri mage (that is, a Wizard) could re-discover the means by which a person can make a covenant like this, but such a discovery is unlikely. It would require the Waziri mage to take very seriously the beliefs of the Kahina (Druids and Shaman), which very few will do, because those beliefs are often very woo-woo, mystical, "ineffable revelation of the spirits" type stuff, while Waziri magic is precise, mathematical, exacting, and rigorous. (The Waziri are often held back more by their collective superiority complex and inability to believe that other traditions have anything to teach them, than they are by the actual limits of their potential power.) That technically only makes it very unlikely rather than impossible, though, and there is one greater spirit (Mudaris, a spirit of memory, history, tradition, and understanding) who would be willing to provide such covenants should there ever be Waziri who seek it. Mudaris actually was the patron of the original group who went on to become the Waziri in the first place, though the spirit was imprisoned in a Safiqi temple for having been corrupted by dark powers; the party has since cleansed, freed, and empowered Mudaris to help in their fight against the Song of Thorns, whom Mudaris helped slay utterly (though that was mostly the party's doing.)