"The Dwarves have extensive records of the births of each of the three children of their triumvirate. By all appearances, the Dwarven Ancestor-Gods were biological when They were walking the earth. I do not think there is insight to be found in the nature of Gods by studying Them before They had ascended. But there is one left in our sample, is there not?"
"Nethu," you say. "Son of Asuryan, you said? Isn't Asuryan supposed to be married?"
"And Ulthuani belief would tell you that when Ereth Khial attempted to seduce Him, He rebuffed her and remained loyal to Lileath. But Nehekhara has the very same myth between the Sun God Ptra, the Moon Goddess Neru, and the jealous usurper Sakhmet, but in this version Sakhmet uses trickery and illusion to usurp the position of Neru for a night. While it is easy to see this as a mythologization of the phenomena you know as Hexensnacht, the similarities are too many to be coincidence. I believe the Kingdom of the Dead preserves a tale that the orthodoxy of modern Ulthuan rejects - the conception of Nethu, who I believe to be known to Nehekhara as Sokth."
So I was going through a few things and filling out my notes as I tend to do, and I'm currently musing on something. Cython here compares the Sun and Moon god and goddess of Nehekhara and Ulthuan, and that got me to to thinking about all the other gods of Sun and Moon in Warhammer.
So I had a little thing in my head that I'm forming into a theory. Disclaimer that this is for fun, but I hope to be informative in the process.
So there is an incredibly notable Old One god for the Lizardmen. His name is Chotec, and he is practically everywhere. He is one of the most revered gods of the Lizardmen, and he is the God of the Sun for them. The Solar Engines placed on the back of the Bastilodons sent to war, and many other powerful artifacts are attributed to Chotec. But you might be thinking, if they worship the Sun, then what about the moon?
Well, the closest thing I've been able to find, is none other than Huanchi. Huanchi is the Old One God of the Earth and Night, whose animal representative is the Jaguar representing speed and swiftness. There is one part in 6th Edition Lizardmen Page 19 which I found very interesting. In that page is a map of one of the four remaining Temple Cities of the Lizardmen in Lustria, Tlaxltan the City of the Moon. Within that page is the description of several temples of the Old Ones in an in-universe voice, likely that of a Skink.
Dome of Huanchi: "Cousin of darkness, Huanchi's priests too shall dwell in twilight."
Sun Temple of Chotec: "Whilst one brother dwells in darkness, his double-twin, exists in light. Behold!"
So you see, the funny thing is, this description set me into the weirdest conclusion. You see, there is another pair of "double-twin gods" who have had some examples of being related to the Sun and Moon. The connection is tenous at best, but I found it amusing.
You see, the Lore of Da Big Waaagh has the following Cataclysmic Spell:
"The Evil Sun - Fuelled with vast power, an Orc Shaman can will into existence a burning core of energy. With great tusks and a leering face, this evil sun descends upon the battlefield to smash all before it."
The Lore of Da Little Waaagh has the following Battle Magic Spell:
"Curse of da Bad Moon - With a chilling howl the Shaman summons a great pale moon with a leering goblinoid face and large, tusk-like fangs."
Gork and Mork being fallen Old Ones joke aside, Chotec, Huanchi, Gork and Mork are gods of Sun and Moon alongside Asuryan, Lileath, Sakhmet (Morrisleb), Ptra and Neru. Except one group see them as husband and wife (Nehekhara, Elves) and one group see them as double-twins (Lizardmen, Greenskins).