Today's question says "Back when John's Scion Resources was still up, there was a goddess in the Slavic mythology section who interested me, but I can't find anything on her anymore. She was called "Chors" and she represented moonlight or something. Do you know anything about that?" Well, as I'm sure you well know, we do know something about that, since otherwise you probably couldn't have seen it on a website we used to maintain. Let's talk about Chors!
Chors - or Khors or Hors, depending on the Slavic dialect and the transliterator - is a celestial deity who appears across different Slavic mythologies in different forms, and she (or occasionally he!) can be very difficult to pin down. All Slavic mythology is, to an extent; we have few records of Slavic religious practices before the arrival of Christianizing missionaries, since it was largely preserved orally and practiced in natural theatres, and what was recorded was almost all by outside sorces. There's only so much faith we can put in Greek writers talking about the strange and wondrous practices of eaterners or Danish historians who were primarily concerned with making sure their readers knew how incorrect the Slavic religion had been in the first place, so we end up with a lot of scraps and side mentions, and folkloric descendents that we have to interpret through a mythological lens.
What we know about the eastern Russian version of Khors, and the western Slovak/Czech version of Chors, is substantially different, so we all get to play a guessing game about whether they were originally two different deities, one deity with different regional forms, or whether our guesses about one are just wrong and the other one is the "real" Chors.
The Russian Khors is very sparsely attested, but we do know that the deity existed. Khors is named as one of the deities that had idols in the famous religious collection of Kiev in the tenth century, which were shortly thereafter torn down and thrown in the river when Christianity became the law of the land, and based on which of those idols survived longest and was destroyed most spectacularly, historians guess that Khors was probably considered the second most important diety (after Perun, the thunder god and personal favorite of like all of Ukraine at the time). The other major image of Khors in Russian literature comes from the Tale of Igor's Campaign, in which a hero must rush to arrive at their destination by "racing against Khors", which is usually interpreted as meaning that Khors is a sun deity, and the hero is attempting to reach their goal before the sun finishes traveling through the underworld and rises for the new dawn.
That mention is the only story-based evidence of Khors as a solar deity, but reconstructions of the name Khors itself also suggest it's based on old Avestan dialectal mentions of the sun, and some scholars have even gone so far as to decide that this must mean Khors is an epithet of the more commonly-known Russian sun god Dazhbog. You'll occasionally see mention of "Khors-Dazhbog" as a composite deity, especially in older books on the subject, for this reason.
You might have noticed that I didn't use any pronouns with specific genders up there, and that's because the Russian Khors doesn't have a clearly-defined gender, as far as we can tell. The very rare mentions of Khors usually use metaphorical language and don't directly describe the deity, which led most later studiers to just default assume that Khors was male, partly because they were dudes themselves and tended to think of important gods as being dudes, and partly because they were equating Khors with Dazhbog, who is specifically referred to as male. And since study of Slavic deities tends to be very Russia-centric, the male-sun-god-Kievan-idol version of Khors is the one you're most likely to find information about in English sources even though we know a lot less about that one!
So what do we get if we head west, though, and leave Russia and the Ukraine for the lands of middle Europe? Here Chors is less well-known through items of worship; we don't have any records of impressive shrines in her honor or idols that once held pride of place in a royal court. Instead, she is remembered in oral retellings of mythic tales, trading in her artifacts of worship for stories of her interactions with the other gods. Western Chors is, interestingly enough, not a sun deity; rather, she is the goddess of the moon, a nighttime celestial deity, which seems like an odd contrast with eastern Khors. But then again, both are deities of celestial light and the passage of time it marks, so maybe they're not particularly different after all, especially since we know so little about the eastern Khors. (There's even a theory that the eastern Khors is also a moon god, and that outrunning Khors in the Tale of Igor's Campaign refers to outrunning the moon before the morning, and another that Chors is perhaps a deity of both celestial lights, rather than being confined to one. So many possibilities!)
Unfortunately, the mythic tale of western Chors is a tragic one (and, unlike many other times we say that, it is not even slightly her fault). As the story goes, Chors was the most beautiful among goddesses, and the wind god Stribog had fallen in love with her. She took no notice of him, however, since she was herself in love with Radegast, god of the stars and nocturnal fires, over whom she quietly pined but who did not seem to recognize her passion. Because he was not nearly as handsome and well-liked as Radegast and knew he could not convince Chors to choose him instead, Stribog decided to instead force her hand. He stole the velvety cloak of stars that Radegast always wore when performing his duties, and waited until the night was almost over and Chors would be weary from her duties; wearing it, he sneaked into Chors' room, and in the dark she could not see his face and thought that Radegast was returning her affections at last, and he made love to her while she believed it was her love.
Radegast, however, noticed the theft of his cloak very quickly and was enraged that someone should be messing around with the tools of his trade, so he sent his subordinate spirits to discover what happened. When Stribog sneaked back to return the cloak, hoping it hadn't been missed, he was caught and the entire sordid story was soon uncovered. Infuriated, Radegast immediately demanded that a tribunal of the gods be called to punish Stribog for his actions, and Svarozhich, king and judge, agreed that Stribog would be punished - by the death of the child he had conceived when he raped Chors, who would not be allowed to be born and reward him for his behavior with offspring.
Chors, understandably miserable and devastated over the entire situation, however, knew that this was likely to be the gods' judgment, so she went before the court and made an impassioned plea to them, begging that she should not have her unborn daughter taken from her in order to punish Stribog (although she would be several thousand percent justified in wanting to punish him, if we're being honest). Since she knew that Svarozhich would require a reason beyond her maternal feelings to save the child, she came armed with a plan: she pointed out that while there were already goddesses of three of the seasons - Vesna for spring, Zhiva for summer, and Morena for winter - there was no goddess of autumn, and the unborn girl could take on that role and oversee a quarter of the year once born.
Svarozhich turned her down, alas; he said that there was no particular need for a goddess of autumn, and that creating one would just encourage the gods to think they could start creating deities of every random span of time they might encounter. At this, Chors began to weep, so movingly that the moon itself wept with her, and begged that she should be allowed to keep the baby at least for a day or two after it was born. Even Svarozhich couldn't resist her sorrow or refuse her, and he appealed to Prove, god of justice, for help, since he knew that he couldn't either punish Chors for Stribog's sins or fail to punish Stribog for his own heinous actions. Eventually, a compromise - at least, by the standards of divine law, which are apparently harsh and unforgiving - was reached. The baby was born, and the moment she left Chors' womb, Svarozhich took the infant from her and declared that there had never been any such baby. She had been only a dream. The infant dissolved into nothingness, but was not sent to the underworld; rather, she became a sort of anti-deity, a goddess who doesn't really exist but whose memory is still important to the universe, and (so the linguistic story goes), her name was Yesen, which is why the word yesen means "autumn" in several Slavic dialects, and why its root word, sen, means "dream".
So the child wasn't killed, so that Chors could be spared the death of he daughter, but she also was never allowed to live, in order to prevent Stribog from profiting from his evil actions. The moon's path across the sky at night is said to be the path of Chors, always searching for her lost daughter, in case she should someday be able to be found.
Alas, this isn't one of those myths with a happy comfortable moral at the end; if it has a moral, it's "there is no escaping justice, even when justice sucks and hurts the innocent", which is oddly enough a moral you get a lot in Slavic mythology, or perhaps "assholes never prosper and they hurt a lot of other people with their behavior as a result". Chors is horribly mistreated and violated by her fellow deities, and in pursuit of punishing them she is punished as well, although she takes a stand and mitigates the terms of that punishment thanks to the strength of her emotion and appeal to mercy. She is undoubtedly a tragic figure, and a rare one at that - normally tragic female figures like this in mythology either die or disappear from the story after terrible things happen to them, because they were created to prove a point and do nothing else.
But Chors remains, lighting the sky over and over, traveling without rest to seek her child (and she is also mentioned to help take care of Myesyats, the moon god, who ages with the phases of the moon, when he is the "child" phase of the early waxing moon), and seeing her continue onward is a peculiarly tenacious and determined role for a goddess with that kind of story behind her.