10 Most Irredeemable Star Trek Villains

This article isn't using kill count as a measure of everlasting evil, but still! This band of problematic aliens from another plane were behind an attack on Earth that cost seven million lives including the sister of one chief engineer. That was just their warm-up act, however; the Sphere-Builders had convinced the Xindi to finish the job of humanity’s eradication.

Depending on how you think about time, none of this should have ever happened, but it did. One of the fiendish factions of the Temporal Cold War, the Sphere-Builders had spied a future they didn't particularly like in which they were sent packin' back to their realm by the Federation in an alternate 26th century. (The way things are heading, they're going to reach J in the Enterprise run long before then, too! Plenty more letters in the alphabet, did you say?)

As the crew of the NX-01 found out in the 22nd century, the species' goal was to transform space in our universe into their own trans-dimensional playground by using the gravimetric energy generated by a vast network of humongous spheres. Had they not been stopped, the spatial transformations in the Expanse would have grown to encompass hundreds of systems, with disastrous consequences for any inhabited worlds in their path.

You can't really get more irredeemable than an attempt at galaxy-level genocide just so you can move into the neighbourhood. The Sphere-Builders may well have started off as good guys the Tuterians in Star Trek Online, but they're always a villain to me.