Biology isn't my strongest science but, if True Kio can breed with any human (humans, Undir, Val, Kio) and produce Kio then can't Kio breed with Kio, True Kio, humans, or Undir and produce something (since they aren't infertile)? That's what I remember of biology/genetics tells me (though, as I said, it's certainly possible I'm wrong).

According to biology, Kio (both True and half-breeds), Dwarves, Dark-kin, Gnomes, Undir, Pengik, Naori, and Val are all members of the Human species or a species so close as to functionally be the same species. If not, they would not be able to mate and produce viable offsping, which we have plenty of evidence that they can. This is (biologically) why Elorii cannot breed with humans: They are far enough removed biologically as to not produce viable offspring. That said, the addition of the "Soul" and "Divine Essence" massively complicates the scientific basis of Arcanis biology, as if memory serves the reason why Elorii and Humans cannot breed has more to do with the Elorii being an elementally attuned bioconstruct race, with their souls being so far removed from the 'natural order' that the metaphysics just don't work.


Interesting Fact: we know there are two 'breeds' of Human (Mandai and Sarosh) who apparently CANNOT mate and produce viable offspring means that the Humans that follow the Pantheon and the 'other ones' (Ossarions and Myrantians?) represent a different species of human entirely. That said, the Mandai humans CAN breed viable offspring from Dwarves, which to me suggests that the playable human race are actually of the same stock as the Celestial Giants rather than the Savosh humans of Arcanis. That said, since it is inferred that the reason Humans and Elorii cannot breed is because of the soul thing, the reason Mandai and Savosh cannot breed may be because the Savosh's souls go somewhere else besides the Cauldron, which complicates the relationships there.

Either way, we know that Kio CAN and DO mate with Undir, Vals, and Humans, and that the Kio bloodline has the ability to 'hijack' the celestial nature of the Val bloodlines to produce the val'Sungha line. This means that they are biologically and metaphysically compatible, but there is something about them that is not quite kosher with the rest of humanity.

At GAMESTORM a few years back Henry cameras the Guest of Honor and I had the chance to talk with him about the Kio and thier history. There will be cool history stuff coming in the kickstarter book eventually that will add details and context.

The True Kio were/are a powerful "elder" race with powers very roughly on par with Celestial Giants and tall elori. I don't think "what they can mate with" is fully determined by Biology...I think they get to write a lot of thier own rules and travel at the speed of plot.

When TK mate with a "mortal race" they produce Kio. And Kio (like Val's) kinda but not fully breed true. The purity of thier bloodlines is very important to Kio. When the Kio stream crosses with Val stream the end result is always a Val Sungha...which rule over the other Kio.

I don't think we know what would happen with a Kio who crossed streams with Gnomes/Celestrial Giants. Gnomes DO still breed true so my best guess in this instance is that you get a gnome. Doubt many (any) Kio have ever "tried this."