The idea is to take a regular city like WL or one of the Elven Nations and convert it into a hunting ground where it appears almost identical but will be populated by monsters from another plane. Haunted spirits, planar demons, zombie citizens and even
evil versions of the actual adventurers present when the Planar Inversion takes place. So say it's a 100th level hunting ground, then when the 100th character uses the Invert Plane command or whatever, suddenly they dissolve into the ether and return to form in the alternate version of that world. If they are in a group, they will all go to the same area otherwise it is unique for everyone.

Dragons r Real