21. The Xindi
The Xindi aren’t a single species of aliens. They are a collection of species that evolved together on their homeworld of Xindi. After countless years of warfare in-between each species of Xindi, they finally came together united after their homeworld was destroyed by their inability to put aside their differences.The threat they posed to humanity came to light when they tested a weapon on Earth that carved a line of death down from Florida to South America leaving millions dead. The Xindi are also a unique group because of their parallel evolution of multiple species from a single world.