what do uzoma and marghan think of each other? does she actually care about her son, or vice versa?
That's a really good question. I think it's possible to love someone without liking them, and that's probably how Uzoma feels about her son. She loves him and she would do anything to protect him...but at the same time, she's aware that he's a little shitbag and doesn't particularly like interacting with him.
As for Marghan, he has a surprisingly down-to-earth relationship with his mother. What I mean by that is, he talks to her like his equal, for better or worse. He doesn't disrespect her, he doesn't talk down to her, he's not mean to her, but at the same time he doesn't see her as an authority over him. Marghan doesn't respect anyone's authority though; as far as he's concerned, he's the highest authority in the kingdom. And he's basically right.
Marghan is never mean or malicious towards his mother, he's just...really dumb, and it annoys the piss out of her. I think that's a sign that he loves her, because he can definitely be a mean, snotty little smartass towards people when he wants to be. He doesn't want to speak that way to his mom. His bodyguards? Sure. Foreign diplomats? Yes. Other Great Rulers? Oh yeah. But not his mom. There's just no desire in him to treat her like that.
And that goes both ways, because as often as Uzoma might raise her voice at him, as utterly flabbergasted as she might get at his behavior, she has never directly insulted him to his face. She's just not that kind of person and she loves him too much to treat him that way. She will criticize his behavior all day long, but she'll never insult him as a person, hit him, or otherwise be mean to him.
That must have made an impression on Marghan, because he offers the same respect back to her.