usually players from the main kingdom that are super selfish and leave the kingdom just so that they can vote themselves in as kings. Not really the choice of the people at all... just someone that take a city under their banner and vote for themselves.
This is what's happening on our server as well. Top kingdom took all other kings with alts and is controlling who gets to participate in the current event. About 10% of the server population is on the leaderboard. Alliance is only dropped for a few minutes at a time.