Try this idea...
Supers show up in this world, but in Russia during the
Time of Troubles. Once they stop fighting among themselves they ally to take over Russia. These supers are generally in the 500 to 750 point range. But in each generation, there are a very small percentage that are much more powerful.
The most powerful by far calls himself
The Firebird and claims to be an Avatar of the old gods now working for Jesus and Mary and striving to become an Arcangel. (If you have Bill Stoddard's GURPS: SUPERS, take the templates of
The Archetype, The Renaissance Man, and the Super Magician and create a ten thousand point super.If you played
Abberrant Divis Mal as a Holy Tsar.) The Firebird, among other talents, had
Charisma +5 and
Unaging, and decided to bring the whole world under Russian guidance and rule in order to promote virtue.
The local year of this Q3 world is 1898. The Firebird maintains a planet-wide
Caesaropapism. However, new supers are showing up in many places, and these aren't of Russian blood however impure. They must be of the devil.
Both the original supers and the new ones come from the same source, the Cabal's interference with a set of powerful artifacts. Each artifact is connected to an element (Disc/Earth, Chalise/Water, Sword/Fire, Wand/Air, Harp/Spirit, Crystal/Mind, Distaff/Plant). By arranging these artifacts in a pattern the world they are connected to can be changed. As the artifacts were bound into the older spell, and couldn't be separated from it without destroying the whole parallel, not just the universe in the parallel, but the parallel itself, even the Cabal feared to do that. So more superheroes were summoned to bring down the first crew.
The reasons the Cabal cares about this parallel are twofold. A) They know the local supers were meant to reshape this world into an instrument of interplanar conquest. They assume they are at least one of the targets. Also, they want o know who started this mess. B)
Reich-5 has found their way, via the Chornobahn, to this world. They assume that the reaction will be bad and messy.
Homeline has been tipped off about the mess too. As little as they like Centrum, a world full of swasher superheroes and villains out of control is worse.
The planetary tech level is TL5. Think of the technology of 1820 with a few more advanced areas to taste. Firebird isn't fond of technology, science, or secular reason. In theory, the control level planet wide is six. Practice varies widely and wildly. The Russian Orthodox Church is both the most effective tool of oppression and one of the few forces that can stand up to Firebird's rule.
PCs can be supers either trying to avoid being captured and made into slave soldiers or hardened rebels. Cabalist and Icops also make good PCs but be generous with the points. This is a dangerous world meant for 500 to 1000 point characters.