The Ascendancy has a monarchy, and heralds to keep track of towns as they map the country, but it doesn’t seem to have much control over the cities. See the herald’s joke about how there aren’t any taxes.
I have yet to play Rayya’s Children to the next tier, but it was my impression so far that they’re pretty loosely tied together through their trading company, rather than a more top-down government. I certainly might be wrong about this now that they’ve added more.
Were the Ascendancy any larger, I could see them becoming a proper Empire. Then, the rulers of the most powerful cities might very well call themselves kings. They seem like the type to call themselves royalty.