Sergei Lukyanenko's Night Watch series already has some links to real-world mythology via the character of Gesar, and possibly also Zabulon. This made me wonder about the in-universe legend of the Fuaran, which was a pivotal plot point in book 3, The Twilight Watch. Is this also based on some real-life legend, or did Lukyanenko make it up out of whole cloth?
Is there a legend of the Fuaran (or equivalent) in the real world?
I did a web search for "Fuaran", but aside from Night Watch references, most of the results were touristy stuff in Scotland. But my web search defaults to English-language results, and this could well be from a Russian or Central Asian myth.