At least 15 years ago, I have read a comic book about a hero from our world being summoned to a magical realm (it might have been a different planet). The magical realm is divided by colors: red, blue, green and yellow. The humans have those skin colors as well, except there are humans with no color at all (pink skins). Those are used as slaves.
Our protagonist turns up to be one of those and is almost immediately enslaved after his summoning. The main villain is the Red King, the king of the red realm. He is a sort of warmonger. His daughter, red princess, gets a liking for the protagonist and makes him her personal slave.
The blue realm wizard is helping our protagonist. We don't see much of the other realms, except for one panel that shows that giants live in the deserts of yellow realm.
The story ends as the red princess is captured and used as a hostage by the blue wizard. The protagonist is then sent home.
It is all a sword and sorcery sort of comicbook. It might be European.