From Introduction:
Legacy of Justice is a post-apocalyptic superhero roleplaying game setting. It is not designed specifically for any particular RPG game system at this point, although the author highly recommends Mutants & Masterminds.
In Legacy, superheroes arose in the early 20th century, creating a “Golden Age” of four-color style heroes. Their superhero tradition very much reflects comic books of the 40’s, 50’s, and 60’s.
Then, in 1969, tragedy fell. One of Dr. Apocalypse’s doomsday devices was actually unleashed, and Fluxstorms were unleashed upon the world. Their aftermath left a shattered world that looked much like a post-nuclear holocaust landscape.
And so people set about rebuilding the world from scratch, but with the constant danger of flux surges, roving mutant gangs, bandits, anarchy, etc. Super powered beings become key leaders in this new society, both as benevolent protectors and as cruel despots. Feifdoms ruled by superhero warlords battle for survival on the flux-shattered Earth.