Just some Theories
King is a titan
He keeps saying he is the king of demons and for that to be true he would have to be a young or weekend titan
The collars he wears weakens his powers
When we get an overview of the isles we see that the titan is missing a horn the same shape and side as kings
Bill from Gravity Falls was once a god on the isles
In many seats we can see depictions of him in the background
HE IS A INTERDEMINALT (is that how you spell it?) BEING
And he has said he has been to a really hot world
The boil isles
Belso is a human/ Luz’s dad
This is very unlikely
They said in the show that Belso came to power about 50 years ago Eda and Lilth are estimated to be in there mid to late 40’s
Luz’s mother is estimated to be around her 30’s
So this is unlikely on the dad part
For human it could be likely for when we first see him he uses a petrified plasmin to gain some sort of power to use the staff
A long time spent in the Boiling isles turns you into something you're not
If Belos is a human and he has been there for a while he has most likely gone threw some sort of change
And if so Luz might too
King = cat
King as a kitten was thrown into the trash
Ep 1 told Luz “cats don't do that” when he landed on his feet and she did not
His behavior is exactly like a cat
King likes to sleep a lot
He calls himself a king and cats most like think that
Sports the theory before this one
If he knew all the demons types why did Eda have to tell him about the puppeteer
King gets stuck in clothes and random things
King gose nya nya when he's happy
His fur puffs up when he's scared
In the Body swap episode when Eda's in kings Body they take King to a cat cafe
King has referred to cats as soldiers