...

Here's a fun little theory/headcanon for you.

Fact: the King comes from Corbeaux.

Now, the city of Corbeaux is only mentioned one other time: when talking about color theory. It's mentioned that the theory originates from here. I think we can safely say that the theory has to do with the Forgotten Country in some way, because when brought up for the firts time, Siffrin has a thought along the lines of "oh this is not surprising to you/you knew this already," which could be read as this being something that was common knowledge back on the island. Maybe it was spearheaded by islanders even!

Now, where else is color theory mentioned? In the star room. There's a Ka Bue book on color theory there. Which is kind of out of place compared to everything else in the room (which is either directly related to the Country or to the stars.)

So here's my theory: the King was originally a researcher on color theory back in Corbeaux. The book in the star room is his- before he got stuck crying forever on top of the House, he probably went to the star room quite often, to try to get anything he could on the stars and/or his country. That's why he's camping in Dormont's house specifically. It's the closest he can get to the island, AND it has a dedicated star research room.