There are many spiders throughout the continent of Orelisle, as one would expect, but a certain kind tend to gravitate towards Binturia and the Underdark. They're typically quite large. They're not too hard to beat in a fight, and in fact the Dark Elves of the Underdark co-exist peacefully with them, since the Dark Elves worship the three Goddesses.
They're creepy, man. Nothing should have that many legs. Or eyes.