you do realize dethrone is at the same time for both servers, right?
anyways, the playerbase covers something like 12 timezones, from the west coast of the states to the east of europe, it's impossible to find times that work for everybody, so they have come up with a compromise that doesn't really work for anybody. Unless Korea turns dethrone into a timed zone (which has it's own sets of disadvantages) there is no solution to this issue.