If Imhotep had defeated O'Connell, he would have killed Evie and fully resurrected his lover. This seems tragic on an individual level, but hardly a catastrophe in the grand scheme of things.
I know he has some sort of zombiefied followers, and the Medjai warned that he was
"a bringer of death"
but are really quite vague about what that means.
So what happens next? Does he conquer the world? Does he destroy it? Just how ambitious is he, and how evil?
According to the film's official novelisation, Imhotep's plan is nothing short of the total destruction of all life on Earth.
Within his cold hell, the skittering beetles upon him and within him, Imhotep knew the ramifications of the portentous curse his burial carried with it, the hom-dai. If he were to raise himself, and his beloved Anck-su-namun, from their respective places in the underworld, they would together be unconquerable; they would unleash upon the world an infection so vile, so indomitable, that a cataclysmic ending would come to all living things . . . all but Imhotep and Anck-su-namun.
That being said, he doesn't seem averse to zombies and unliving things, so he'd probably keep some of those around.
