Gruumsh's wife Luthic, orcmother and goddess of fertility, left Gruumsh One-Eye to marry a mountain, the chosen of Sune led and fucked a group of adventurers across the land to take Gruumsh's stolen eye and give it to the mountain as a gift so he wouldn't leave Toril (the mountain is sapient, and could theoretically stand up, to be fair) This is one hundred percent canon the book is called The Watcher
For reference: Loumara are a group of Demons like Tanar'ri and Obyriths. Most D&D Demons are Tanar'ri, which are big snarly monsters naturally shat out by The Abyss. Loumara and Obyriths weren't a thing until a 3.5 supplement, though some pre-existing Demons were grouped into them. The term "Tanar'ri" was attached to Demons during the Satanic-Panic when TSR was afraid to use the term, but later got retconned into a specific taxonomy. Loumarra are incorporeal possessing-force Demons. Kind of like how a lot of people thought things like sickness/mental illness were the result of demonic possession. The only one stated in 5E is the Dybbuk, which is a Demon from European Jewish folklore that possesses corpses. Other notable examples include a kind that possesses weapons, and turns the wielders into blood-crazed warriors, and one that possesses sleeping people to make them do sleepwalking crime. Obyriths are ancient, Lovecraftian Demons from the universe that came before our universe. In 3.5 where they were introduced, they all had madness mechanics, but that aspect was dropped. The only one with 5E stats is the Sibriex, which is a flesh-warper. There's also outsiders that turned into Demons like Lolth and Graz'zt. They don't get a group name.
never heard grazzt was an outsider, always heard he was a devil first. he also acts like a devil. pale night probably isn't a typical obyrith though and she's associated a bit with him.
Did any of them marry mountains as well? Or just the one Karlach met? Who knows, Lolth's first spouse could've been a badger named Barry for all we know.
@@carolynv8979 Spoiler alert: it didn't. It's essentially the same as people who are stupid enough to bring the person who has a relationship with them to live in the same house. The so-called "stable union" (at least in my country).