I mentioned this in another thread but I thought it deserves it's own discussion, concerning inspiration taken from LOTR books by Tolkien and previous KQ games. Albeit in limitedly and not direct copycat of the stories of course.
According to Roberta Williams, Tolkien was inspiration for some of the material in KQ8 with her attempt at epic fantasy... That's largely were the Orcs came from... Along with other high fantasy archetypes in that game.
However, LotR also inspired elements of previous games.
The Tolkien spelling 'dwarves' is used for the dwarf race in KQ2 (and later in KQ8) and within the
KQ1 manual, as opposed to the traditional spelling 'dwarfs'.
The twin snakes statue in KQ5 is also a reference to black Watchers at Cirith Ungol, a gate into Mordor from Return of the King! Sam held up the Galadriel's crystal vial to counteract the deadly force from the statues eyes (see RotK, book 6, ch 1.).
This is actually one of the most direct concepts taken from Tolkien's story and readapted into the KQ world (rather than just adapting races from the books). It's also in my opinion a great example how Tolkien can be incorporated without feeling out of place at all!
Actually it really depends on what Tolkien works you are talking about the Hobbit is more fairy tale/children's story for example. Somewhat different from the trilogy which was written for grown-ups. The Silmerillion would be even more removed, although it is quite mythic and legendary, and even biblical in it's own sense.
I don't say this in all seriousness, but rather than dropping a ring into mount doom, Graham drops cheese into a strange machine!
But seriously Roberta went to many sources for inspiration not only fairy tales but even classic fantasy and even horror.