Wasn't the point of making all these new deities a way to make Therafim a more unique setting? What the heck is Baba Yaga doing here?
That's a very good question, and I'm sure that I have a decent enough answer. The simple answer is, I've always loved Baba Yaga, and I just had to have her in the setting. Now for the longer answer. The stories about her are insanely awesome, and I love 'em all. Besides that, she's an established D&D character, from way back in the feature-length adventure module "The Dancing Hut of Baba Yaga" in second edition. So, of course, I set about putting her into things, but, as I was tinkering with her, the name Baba Yaga just fit. Anything different cast a whole different sort of light on her, and also made it seem to me as though I was trying to one-up a legendary being.
http://en.wikipedia.org/wiki/Baba_Yaga should give most readers enough information about Baba Yaga to give them a decent start on understanding her, and where her name came from. It was as I was reading over the etymology of her name that I realized the linguists had guesses that made sense, but, as in so many cases, really didn't know for certain quite where it came from. With that air of mystery about the name of Baba Yaga, I decided to keep it as it was without shame.
Baba Yaga almost made it into the Forbidden Gods, or maybe the Mortalborn Gods. After some thought, though, I realized that she really wasn't suitable for either category. The legendary creature Baba Yaga has been known to be genuinely helpful on occasion, and she certainly isn't interested in the annihilation of the world, or in any sort of twisted orgiastic rites. She's a cranky old woman who happens to also have some terrifyingly immense power. She's not Mortalborn, either, because she has way, way too much personality, and she's not terribly inclined to help out mortals much anyway, except at her whim. Demigod status fit her perfectly, so there it stays.
