One of the producers, Ulf Norström, found the name for the movie in a dictionary. "Rex regi rebellis" is latin and means "the king is rebellious towards the king" or "you are your own enemy".
There are two kings standing on a chessboard in the dream sequences. They are referring to the title of the movie. "Rex regi rebellis" is Latin for, "the king is rebellious towards the king".
After reading the script, Kaj Stenberg was more interested of playing the role of Tor Condrup, Klarks boss, instead of the main character.