Humen

The humen (hitojin ひとじん) are the indigenous people of Barzakh. The World Government considers them to be the antithesis of humans, so much so that it is a felonious crime for any human (humans) other than the Gorosei and the World Nobles to interact with any human (humen) regardless of whether or not the interaction was purposeful or accidental.

Physiology
Appearance-wise, humen are no different from humans. But genetics-wise, the differences between humen and humans are great enough to prevent either of them from reproducing with the other. Thus making the very existence of a hybrid an exceptionless impossibility.

Needless to say, the genetics of the humen also prevent them from reproducing with any of those species whom are capable of reproducing with humans.

History
WIP...