I couldn't find quiiiite what I had in mind, and I'm struggling with an idea I love.
In our campaign, there are three PCs: the human rogue 5 (looking at noble scion at level 7.) His father was Noleski and Natala's brother, but he was dis dishonored, disowned, wiped from the books (so much as they could,) and eventually murdered. His mother is from House Orlovsky, and his sister married into House Garess (this happened before the bad bits, and all of that occurred before the disappearance of House Rogarvia.) He is fairly good at playing the political and social game in theory, and when he talks to the other PCs, but he feels like he deserves more and has a LOT of pride... I'll come back to that bit.
PC two is the aasimar (witch 5.) She was a schoolmate of his, but from MUCH humbler background (she essentially got a scholarship.) She's the big diplomancer, and does her best to clean up when he stumbles. She has, up to recently, thought he would be an excellent ruler, if maybe in need of a little refining.
PC the third is the dwarf (forgepriest 5.) Crafters wanna craft. He is a fairly chill, all things considered, he follows his lawful good alignment. He has little interest in the politics rapidly catching up to them, but he will do his part to ensure the safety, stability, and prosperity of their settlement.
Behind the scenes, I have a struggle going on between Noleski and Natala. They have always been close, and what their brother did wounded them deeply. Noleski chose this sort of exile as his punishment, but that wasn't enough for Natala, who was the one who ensured that tragedy occurred. A terrible accident, to be sure, which brought the remaining siblings that much closer. However, Noleski has, in recent years, become more independent, and is ready to be married and marry his sister off as well (while fairly sly and a bully, he is competent as King and does well, and wants the best for a sister that he genuinely cares for.) Natala does not agree.
She has also been watching (human rogue) for years, deciding whether he is useful or not. She helped orchestrate things to make she he was on this little adventure, and intends to either use him as a pawn, or ensure tragedy strikes again.
As we have played, it has come to the portion tonight that a council of various individuals involved (this includes heads of houses, the Surtova rulers, and a few other NPCs) gathered and nominated who they would like to see as ruler (essentially, who they recognize - there is a LONG story as to why this is taking place this way, but the end result is this.) They chose (human rogue.) BUT. He had to renounce ties with the sword lords, recognize House Surtova as rightful rulers (for now anyway) of Brevoy, and renounce his last name (which was Surtova as well.)
He agreed, threw what equated to an eloquent tantrum and peed in their Cheerios, and left.
Finally, to the question part:
A PC has asked (OOC for a while) if there could be a spy from Natala, who has watched her nephew during book one. I would love this, as I would like to have a fairly significant betrayal, but I'm really not sure who would make the best choice? They have a LOT of people though, honestly. Oleg and Svetlana, Kesten Garess (with three additional guard and a new wife,) Happs the now former bandit (along with at least five others, one of whom now has a wife and young child,) Akiros, J'hod... There are lots of options. But who would you think might make the best spy? And a fairly capable one to not be discovered yet? Or is there some other way she could be watching them?
Kesten works just fine as a spy/protector sent from Natala. (Technically the Swordlords of Restov sent him, but Natala could have suborned him, or could have leaned on the Swordlords, or whatever.) If you don't want to use Garess, one of his guards could easily be the agent.
Oleg or Svetlana might also be the spy -- Natala could have had one of them reporting to her occasionally, an agent-in-place just watching the southern frontier, who rapidly got new orders when the nephew showed up. Having Svetlana turn out to be, oh, a level 3-4 rogue instead of a level 1 commoner might be interesting.
I don't see Akiros (who has a well-developed background coming from the opposite direction, down in Taldor) or Jhod (Erastil's priests are more with the village than with the city or nobles, as I see it), but I suppose if you want to rework their backgrounds it's doable. Ditto Happs and the former bandits (it's possible, but would be some work.)
Bring a Lover in to the Mix. A Happless, Charisma 16+ woman being attacked in thier town. He saves her, unknowingly inviting the spy in. She of course falls in love with him.