Claudio Kilgannon is the main character of the story The Amory Wars, which is the concept behind the albums of the band Coheed and Cambria. The setting of this story is Heaven's Fence, a locale also commonly referred to as The Keywork although these two are not the same thing.
The story is further explained in the Album's accompanying graphic novels which are written by Claudio Sanchez, the frontman of Coheed and Cambria. Claudio Kilgannon is in many ways an alter-ego of Claudio Sanchez.
Many sites and individuals on the Internet have taken many different approaches to attempting to "extract" the story from the Coheed and Cambria albums. One such website is Cobalt and Calcium which has combined what they know of the songs and graphic novels with transcripts of interviews with Claudio Sanchez to attempt to chronicle the progression of the Amory wars.