Outlander

The Outlanders are a race of imperialist humanoids from a planet far from Earth.

Biology
Outlanders are externally indiscernible from Humans, and have not shown any differences in physiology. Internally, they possess red blood.

Culture and society
The Outlanders have a tremendous thirst for territory, so they have invaded, conquered, and colonized many worlds, killing off the native species. Among the worlds they conquered and colonized was the Moorwen's homeworld, with the Outlanders justifying their conquest of the Moorwen homeworld by claiming the Moorwen were nothing more than animals. Outlander soldiers tend not to openly speak out against the orders of their government, even if they do not agree with it. They use powerful weapons and advanced armor fabricated with a metal capable of harming Moorwens.

It would appear that they seeded Earth in some fashion, either colonizing it or initially seeding it with life, thus quite possibly explaining the unusual similarity between Humans and Outlanders, with Earth referred to as a "seed colony." It is also interesting to note that the Outlanders had considerable information concerning the Earth and its inhabitants, likely because Earth was once a seed colony, although they appear to not frequently fly by the Sol System.