So my brief reading led me to Åke Ohlmarks, a Swedish scholar who published some really, REALLY bad Swedish translations of Tolkien's works. He'd take a number of extreme liberties with in-universe words and their meanings (as an example, if I recall correctly he referred to Rivendell as something like "River-dale"), as well as just simply not being good enough at English to translate any of it well. He didn't much care for Tolkien's work either, since he considered it juvenile. It was really not well-received, with even Tolkien declaring it pretty shit.
Some time in the 70s-80s he got a bit salty about all the flak he was receiving for it, developed a bit of a complex against the Tolkien estate, and released a book detailing Tolkien's links to "Nazi occultism", which I suspect is where the accusations of satanism and castle orgies come into play. The book's name is Tolkien och den Svarta Magin (Tolkien and the Black Magic) and I'll award one (1) Kiwifarma-karma to anyone that can find the PDF or some other scanned version (2 if you can find it translated). From what little I've read and managed to deduce through the language barrier is that it has some prime Jack Chick-esque cow material in it.
But if you're still worried, let me put your mind at ease and say no, Tolkien, and everyone associated with him, were categorically not satanists, never hosted orgies, and never tried summoning any qt3.15 succubi. The unquendor are yankin' yer chain.
TL;DR early example of modern attitudes to localization.