The devil ( usually called Mephistopheles , as he is in Goetheâ s play ) tells Faust he can help him to do this , but that in the end Faust will have to give him his soul and go with him to hell . In Faust 's study , the poodle transforms into the devil ( Mephistopheles ) . Faust makes an arrangement with the devil : the devil will do everything that Faust wants while he is here on Earth , and in exchange Faust will serve the devil in Hell .