Narsus will be right at home in this place! If anyone wants help getting around a bustling marketplace in a desert city, he's definitely the person to ask about fitting in.
For himself, aside from shopping and enjoying the city, he's going to be gossiping with the locals and getting all the information he can about the old king, the new king, how the nobles are reacting to the change, and the activities of the Syndicate once he learns of them. He won't be judging anyone to start with - it's entirely probable that some nobles deserve to be poisoned and/or disappeared - but he would like to know why it's happening. He's certainly not trusting of Astoria by any means, but the entire situation hits close enough to home that he is going to be drawn in by curiosity whether he means to or not. Think of it as practice for putting Prince Arslan on the throne.
Narsus
For himself, aside from shopping and enjoying the city, he's going to be gossiping with the locals and getting all the information he can about the old king, the new king, how the nobles are reacting to the change, and the activities of the Syndicate once he learns of them. He won't be judging anyone to start with - it's entirely probable that some nobles deserve to be poisoned and/or disappeared - but he would like to know why it's happening. He's certainly not trusting of Astoria by any means, but the entire situation hits close enough to home that he is going to be drawn in by curiosity whether he means to or not. Think of it as practice for putting Prince Arslan on the throne.