All of the continents have already been established. Inazama City is an independent nation out side of the big seven. Inazama controls Both Koreas and Japan. Everything else is under the newly formed union.
I did have that idea of Deadman Wonderland like Prison be formed in one of the cities. But I realized that the Seven Cities Union is not really evil, it more of a way to be prepared in case of Superhuman attacks like Newdeath. That's why They will call it The Anti-Death Protocol. Its up to our character to try and regain the trust of the people again. Or villains to try and start another war to try and demolish the current order and make their own.