5. Mirror Universe Hoshi Sato (In a Mirror, Darkly - Enterprise)
Ah yes, Hoshi. An unusual choice you might say, but hear me out on this one before you lay down the judgement of the Q Continuum upon me. For the only time in Star Trek history we have two episodes that, by technicality, do not feature any of the actual main cast only their mirror counterparts and there is no personnel crossover at all. What we get is full on aggression, deceit, war, lies, you name it, and all in the name of securing at first the starship Defiant and then, Earth. What of Hoshi though? Cleverly she spends 99% of the story moving carefully around in the background, allying herself with Forrest then Archer as events develop, but she ends up being top dog and claiming the throne as Empress as the screen fades. Indeed, you have to congratulate her for throwing such a curve ball and playing out the long game. Had we ever set foot again into this universe with Enterprise we could well have been seeing a returning Mirror Sato as a major villain but cancellation put a stop to that. We might also have also seen Shatner back as the Mirror Universe Kirk too. There was a lot to like about the Mirror crew and I could well have chosen any of them at random to fill this place for their duplicity; Mayweather in particular stands in second place but still a good distance from Hoshi Sato. For now though, Mirror Hoshi holds up in our rundown of awesome minor villains because she set one foot into a bigger league. Whether she kept that foothold is up for debate but this is one person who could predict the way the wind was blowing and align herself in the wings ready for her chance, and none of us noticed until right at the last minute!