fortunately now that I have a plot I can wantonly wordbuild for my own entertainment
basically the classification system is based around the mental inclinations of a species rather than their physical characteristics, since i’ve already come up with some WACKY shit for physical characteristics and abilities
basically, the two ideals of alien species are Angels and Guardians, an Angel being a creature of pure exploration, with their life based around travel, and heavily inclined towards social interaction within their species, who generally have no specific purpose, wheras a Guardian species generally has a very specific purpose and has a psychological need tied to that purpose, and often also to a physical or semantic space
Angel-like species’ tend to be more populous amongst the galaxy but Guardian-like species’ tend to be much moore powerful within their specific domains due to highly specific adaptations, the most extremely Guardian-skewed creatures being like demigods
it seems a more helpful categorisation for cryptoxenoanthropology than “EVIL, BAD, VIOLENT, vs. good, peaceful, smart!”