Well, Nephandum could be considered similar to Cthulhu, but all in all it's quite peculiar. Inside the book you'll find feats, prestige classes, spells, equipment and also many ideas to build a character for a horror campaign, but you'll also find suggestions for building a nephandic campaign, one in which the PCs have to fight against five almost-divine-entities who try to ensnare the world in fear...
Stay tuned, we'll post more info soon!
Marco