So I was just in the void and defeated the final boss of the first stage. So when I wanted to go into the portal and it said that I need to move out of the capital....but I just can't cuz I'm playing on an older server and when I would move everyone would just crush me in the second that i would move out. So maybe you can make something similar like ranks you know....If you stay in the capital you need to be this and this level. So if i would wan't to stay in the capital and go to the next stage i would have too be level 15 or idk maybe pay with honor ,gold etc.
As long as your kingdoms has any cities with a governor on, you can move into the city, immediately run back and click through to the next stage of the Void, and have the governor immediately bounce you back to the capital. The total time you need to be in the city is 30 seconds.