every character has unique traits and makes it very difficult to list the favourite ones... but , here we go, not in order of likeness as I equally like them:
Crown Prince: i enjoy his grumpiness, his deep voice, his sense of logic and objectivity ( he even doubts his own mother, the Queen)- He is adorable ... his moments with UK are unmissable, they keep calling for each others, and we all ship for them ❤️?
UK: from being a rejected kid ( by his father and repeatedly by Park Jin ), his character has evolved into a self confident young man, thanks to Mudeok/Naksu, ( and of course the unconditional love of Maidservant Kim) - I like the UK before the change ( spoiled and apathetic about his situation) and the way he is now ( determined but still temperamental... which is what we like of him..)
Naksu in Mudeok body: here we have a former dangerous assassin stuck in a body which for some reasons, which many have already theorised , doesn't allow her to use her powers- because of these physical limitations , because she is not longer a killing machine, Naksu is discovering herself for who she really is, while adjusting to a more human/normal life, thanks to UK's patience and understanding. Every single moment she and UK are together is worth watching- they are great together.
Master Lee: well, he is undoubtedly the most open minded character- doesn't judge, he is open to new possibility and doesn't go by the book. He believes people can make their own destiny, which is what he is doing with UK and Naksu: He is well aware of their potential ( seen as danger to others) - But himself, is not scared of it, on the contrary, is given them a chance to decide for themselves. I LOVE HIM!
I like everyone else equally so i wouldn't be able to add another one, but I can tell you who I dislike the most: SO-I: not only she is selfish ( surely for self-preservation, and perhaps as a result of a super sad background story which will be revealed to us viewers in some of the next episodes , of course) , but her character in AoS is useless, as we all know that her lies will soon be exposed and she will die by hand of Jin Mu. ( if not him, by someone else for sure... unless Yul will try to save her again ?????