Star Trek: Voyager did a great job of establishing some major villians during its seven-year run. Species 8472 and the Hirogens come to mind, but when you think about really scary enemies who could give Voyager a run for its money, the Kazon don't even make the top ten list.

Introduced in Voyager's pilot episode, "Caretaker," the Kazon were meant to be a formidable species with an aggressive, territorial nature. Though they tried to come across as frightening (and even managed to give Voyager some serious trouble in a few episodes), overall, they just weren't that intimidating. Sure, they brought the weapons to the battles, but, in the end, they just weren't compelling enough to be the ultimate warriors to defeat Voyager or really even stay in the battle very long. They were phased out as the series went on, though, they appeared in every season of Voyager.

Perhaps it was...