Who is H.P. Lovecraft?
Howard Phillip Lovecraft was a writer who was born in 1890 and died in 1937. Although the number of his works is low, he managed to influence many other writers. Many of his stories were placed in the same universe: one where humans are quite insignificant in relation to the horrors that we unknowingly share the world and universe with. Other authors borrowed this setting, adding to it, modifying it to suit their needs, but Lovecraft did it first. The name of this comic strip is a spoof on the name of one of his short stories: "The Call of Cthulhu".
What is the Necronomicon?
The Necronomicon is a book that was scribed by the "mad Arab" Abdul Alhazred. According to some, reading it can drive one insane. All agree, however, that the book is a wellspring of rituals, spells and other miscellaneous dark lore. A must have in any well stocked library. Note: Several versions of the Necronomicon do exist in print. Neither is this book.
What type of creatures are Freddie and Walter?
I don't know what, exactly, Freddie and Walter are. While they possess some of the qualities of Cthulhi (AKA Star-spawn of Cthulhu), they lack others. For instance, Freddie and Walter lack the Great One's wings, corpulence and general ability to reduce any who gaze upon them to gibbering wrecks. On the other hand, they do have a face full of tentacles and they do have residence in R'lyeh.
Where is R'lyeh
R'lyeh is the underwater city where Cthulhu sleeps. It's also the home of Freddie and Walter. Lovecraft placed R'lyeh in the Pacific ocean, but other authors have placed it where ever it served their purposes.
Where can I find out more about the Cthulhu Mythos?
You can find the Cthulhu Mythos FAQ at http://members.tripod.com/~danharms/mythos.htm.