Murdoc is based on The Rolling Stones guitarist Keith Richards, Creeper from Scooby Doo, and Baron Von Frankenstein.
After becoming a Satanist, he began making deals with the devil and came to an arrangement with him. If Murdoc was to become a famous rock star, he would offer Satan his soul. When the deal was finalized, Murdoc acquired Satan's bass guitar "El Diablo" and his middle name was changed from "Alphonce" to "Faust".