(I went ahead and followed Wilshire's suggestion so that I wouldn't clutter the other thread with this.)

I'd like to keep discussing Dûnyain genetic incompatibility with the worldborn as it really fascinates me (despite my unwise tendency to try to look at it with real life genetics in mind). In the other thread there was speculation about what other factors besides "native intellect" influenced genetic compatibility - there is evidence that there's more than that, just from looking at the examples of Kellhus' concubines who were all chosen with that one factor in mind.

I've also wondered about the "nameless children" and if the specific deformity of Kellhus and Esmenet's child (eight arms, no eyes):
a) was something common to the others (whose deformities are not elaborated on) and derived from something specific in their genes (whale mothers? Nonmen?)
and/or
b) had some underlying symbolism to it (admittedly, that's a stretch, and maybe just me extrapolating from the fact that it is something rare in humans in real life).

Yesterday I was flicking through the books searching for a quote to use in my signature, when I happened to glance upon Iëva's birth and death years in the appendices of The White-Luck Warrior. In that book, Achamian has his dream of Nau-Cayûti's supposed death and Iëva is mentioned as "his wife of seven years".
We know Nau-Cayûti's "death" took place in 2140. Therefore, they were married in or around 2133 - and if you look at their birth years, Nau-Cayûti (born 2119) would have been 14 at the time, which is already fairly young, while Iëva (born 2125) would have been only 8 years old... I doubt that this is a mistake (the timeline and related math seems to be pretty consistent throughout this series), but still, eight seems a bit too young even considering that royals might marry at very young ages. Presumably, Celmomas was the one to arrange the marriage, and the main purpose would be, of course, grandchildren to continue his line, but Iëva wouldn't be old enough to have children for quite a few years...
I was left wondering if this could be a situation similar to that of little Lady Ermesande Hayford in A Song of Ice and Fire, who was married off as an infant because she was the last of her line and so her wealth and lands would come into possession of her husband's family. (Completely speculation on my part, but there's no evidence against it either, so that's what I'm choosing to believe for now.)

And yes, maybe I'm just overthinking this small detail, but it kind of makes me see her character in a somewhat new light. You have this "treacherous wife" sacrificing her husband to save her own soul. More understandable if you consider she was only fifteen years old instead of twenty-something?