Once, Nathaniel Essex was a biologist in Victorian London. Realizing that an increasing number of human mutations signaled the beginning of a new evolution, Essex put aside morality in his pursuit of perfecting the human race. A long road of unethical experiments on unwilling subjects eventually led him to incredible discoveries and even greater personal power. Becoming something far more than human, Nathaniel trans-formed himself into the nearly immortal being known as Mister Sinister.
Mister Sinister views the mutant race’s eventual dominance over the world as a foregone conclusion, and that now we must look beyond the next step. Believing that certain genetic bloodlines possess greater mutant power than others, Mister Sinister has targeted members of the X-Men as potential experimental subjects. Regardless of the opposition, Mister Sinister will allow nothing to impede his quest for evolutionary perfection.