Who knows Uk is the king’s star?

In part 2, everyone knows Uk as someone who was revived through the ice stone and who has the ice stone. They called him a monster cos he was dead and revived. If they knew that Uk was the king’s star, they wouldn’t avoid him.

Master Lee, Uk, Naksu, Park Jin, Jin Mu & CP were the only ones who knew that Uk was the King’s Star even in part 2.

In ep 19 of part 1, at 39:30 min, they talked about the King's Star.

Uk told the CP to take the credit after the rain.

Mages from Unanimous were bowing down to the King's Star. Uk is quick-witted so there is no way that he doesn't know he is the real king star. CP knew it right away too. That's why he looked back.

 Muhis:

I don't think he knows that he is the late King's son, spiritually

Yes. I should also make who knows Uk is the Late King's son, spiritually.

 Zdzislawa:

Does Uk know about himself? I was curious about it, how it was never mentioned by Uk or with Uk regarding the king's star. 

Yes. Uk knows and he never mentions cos he is quick-witted.

He just wanted the CP to keep taking credit and feel the insult/burden for what happened to MD. Uk is suspicious of CP for being on Jin Mu's side after MD's death.