I know the show makes a lot of Lord of the Rings references, one what I believe is a dragon ball z reference and if Yogo's powers aren't a reference of the portal gun from the game Portal that is one weird coincidence.
If you watch the movie "The Quest for the Six Eliatrope Dofus" there is an episode where the main cast visits another kingdom but other than some brief mentions and glimpses in this and season 2 you never see the other rulers in the show playing a role. Other than maybe a mention from a supporting character.
I heard that the writing was done for season 4 but the french company was waiting for Netflix to green light it for production, one of the directors said if the series did get the 4th season cut then season 4 might get released as a comic book. (I tried to find the original source of this information, but the post seams to have been taken down)