OK...summary coming up!
Remember the Monitor from the original 'Crisis on Infinite Earths'? The guy whose job it was to safeguard the integrity of the Multiverse?
Basically, at the end of Infinite Crisis, where the Multiverse was resurrected, each of the 52 new worlds ended up with its own Monitor, and the all of them worked together to perform the same function as the original. They all used to be clones of the original, but started evolving personalities of their own to suit their own universes, hence why they all look different now.
The guy who got exiled, Nix Uotan, was basically exiled for being the token liberal amongst them...
Hope that makes some sort of sense...
