I may be mistaken, but I think I saw something about that there are those who believe that cthulhu and the elder gods exist. Is this true?
It is not safe for one such as you to ask these questions. Turn back now, before it is too late.
Yep
http://www.straightdope.com/mailbag/mnecromicon.html
Readers of the pulp magazines were amazed at the same names appearing in stories by different writers, and so began the notion that they were “real.” Dan Clore writes: “This [multiple referencing] creates the impression, amongst naive readers, that author A and author B are not borrowing from each other–or even from the same source, but are instead borrowing from sources which had in turn borrowed from earlier sources, which in turn were ultimately derived from a single ur-source and which reveal the traces of evolution over time, much as the variant versions of real myths do.”
Lovecraft enjoyed it enormously. He wrote to Robert E. Howard, in 1930, that “I think it is rather good fun to have this artificial mythology given an air of verisimilitude by wide citation.” And in a letter to William Anger, in 1934: “For the fun of building up a convincing cycle of synthetic folklore, all of our gang frequently allude to the pet daemons of the others–thus Smith uses my Yog-Sothoth, while I use his Tsathoggua. . . . We never, however, try to put it across as an actual hoax; but always carefully explain to enquirers that it is 100% fiction.”
The Cthulhu Mythos (thanks largely to what S.T. Joshi calls “Derleth’s rabid enthusiasm”) took on a life of its own and “inspired a legion of hacks to produce unwitting parodies of the writer they were misguidedly attempting to honor.”
Some critics have foolishly suggested that Lovecraft took the Mythos seriously. His letters make it clear he did not do so–in fact he depicted “degraded cults and covens” (Joshi’s words) with scorn.