Apart from that, I had very little use for it. So, I was quite pleasantly surprised when I found out that Eric was a retelling of Faust, going so far in the book as to cross out the word Faust at the top of each page and writing Eric in its place.
The story is based on that of Dr. Faust (or Faustus), who makes a pact with the devil for three wishes. Only the Doctor in this story is none other than preteen Eric, complete with pimples, who calls for a demon only to be sorely disappointed in Rincewind the wizard. What are Eric's three wishes that he expects Rincewind to fulfill? Simple.
1. to be king of all the world
2. to have a smoking hot babe
3. to live forever
The problem? Rincewind. None of the wishes turn out the way Eric wishes them to due to their being followed by the King of Demons, who is upset that his filing and organizing was disrputed by a summoning gone bad. In another literary nod, this time to Dante's Inferno, the King of Demons has disrupted the various layers of hell by instituting new policies, replacing torture with boredom.
The historical allusions are also hilarious. The reader meets the Tezumen, who think Eric is their god come to life, Quetzovercoatl, the Feathered Boa, an homage to the Aztecan Quetzalcoatl the Winged Serpent. There is also the Tsortan War, in which Eleanor of Tsort was kidnapped.
Quite certainly the most enjoyable version of Faust I've come across. The joy of reading Pratchett is finding the allusions and parodies he places in his books. It's never a dull ride!