It has long been understood that interspecies fertility is the stuff of low-rent horror cinema and whimsy, and thus assumed that transgenic sapience (pejoratively, Illbreeds) could only arise through meticulously designed procedures.

While simplistic, this view went unchallenged until the discovery of the unique properties of the Mind's Eye family of fungi (named both for its pleasant hallucinagenic effects when ingested and the characteristic result of a human/Kel-Tiar transgenic).

The fungus's evolutionary origins and system of origin are obscure - it spread along interstellar trade lanes for possibly millenia before it was isolated. While rare, it can be found in many environments, due to its remarkable ability to co-opt the genetic structure of local organisms, rapidly mutating into (occasionally) useful evolutionary paths.

For unknown reasons, a strain of Mind's Eye adapted in the 5th millenium s.y.v.p to survival in the human bloodstream. While in almost all cases harmless, the fungus can in rare circumstances attempt genome exchange with a host's germ cells. The result, if viable, is a transgenic offspring of same-species parents - also, depending on the cultural advancement of the host civilization, recriminations, strained family bonds, and general opprobrium.

—Heichner Kzolknov