Alcadizaar the Conqueror

He was an absolute badass conqueror, who defeated the undead in countless battles in landscapes to the far south of the modern old world, before eventually suffering a decisive betrayal that crippled his legions at their moment of triumph, giving the quickly replenishing armies of the dead time to reconsolidate, and thus, seize the initiative in the war. Finally, after an innumerable number of battles had been fought over a period of thirty years, the hordes of the undead had forced Alcadizaar's armies back into their own territory. At this point, Alcadizaar was massively unpopular with the traditionalist senate that had heretofore ruled the republic in Alcadizaar's stead, and was betrayed once again on the senate floor, stabbed to death by some of his most trusted allies in the senate. The republic couldn't sustain the losses it was taking in it's ceaseless wars against the undead, and once deprived of the influence of their great martial leader, the republic fell apart.