Frankenstein is the name of the maker, but we always think of the monster...
And what a monster he is. Frankenstein is a splendid creature, in almost every respect superior to humanity: smarter, stronger, and able to endure extremes of heat and cold that would kill a normal person. He is also effectively immortal.
Such a being, released into our world, would sooner or later come to rule it. Welcome to FRANKENSTEIN REX.
The monster's ugliness is a positive advantage: his towering height and ghastly face scream power; and people, who understand that power is never pretty, that it is brute and unpleasant and that our best chance is to have it on our side rather than set against us, flock to follow him. In a few years the monster conquers Europe, and in a matter of decades he rules the whole world.
But although generations come and go believing their world-dictator to be immortal, the creature himself now understands that he is dying. After an age of deathlessness, the Creature and his supporters must face the cruel inevitability of mortality.
Frankenstein Rex is a meditation on the nature of power. It is a conventional position to consider the tyrant as a monster - to think of Hitler, or Mao, or Stalin as monstrous aberrations from the human norm. By making the monster the tyrant, Roberts invites us to think about how ordinary and how conventional such figures actually are.