Not a great deal of analysis is needed to track the effects of Mephistophilis on Faustus. The changing effects are rather clearly demonstrated in the text. [Note: Marlowe's Doctor Faustus spells the demon's name as Mephistophilis while Goethe's Faust spells the name Mephistopheles.]
In the beginning, Mephistophilis effects Faustus with no more than amusement. He is happily surprised that he can order a demon of Lucifer around so easily. Faustus feels superior to Mephisto and condescending toward him.
FAUSTUS. I charge thee to return, and change thy shape;
How pliant is this Mephistophilis,
After Mephisto begins to impart information to Faustus, Mepisto effects him with a sense of appreciation. This appreciation is not longlived though. Soon Faustus is effected by scorn and hatred. The book of the cosmos given Faustus by Mepisto makes Faustus regret and long to be reinstated among God's followers.
FAUSTUS. When I behold the heavens, then I repent,
And curse thee, wicked Mephistophilis,
When Faustus receives rebukes and Mephisto brings Lucifer, then Faustus is effected by fear. Lucifer enters with Mephisto and subjects Faustus to an entertainment by the Seven Deadly Sins with the intend of bringing Faustus into submission; the attempt is successful.
As the Chorus explains, Mephisto's effect on Faustus is to entertain him. They visit many places including the Pope's court where Mephisto makes Faustus invisible so he can play tricks:
FAUSTUS. Then charm me, that I
May be invisible, to do what I please,
Unseen of any whilst I stay in Rome.
The ultimate effect Mephisto has on Faustus is to terrorized him. Since Faustus begins to respond to the Old Man's encouragement that Faustus seek forgiveness and repent, Mephisto promises that not only will Faustus's soul suffer in hell but that his body will be dragged down and suffer torment there too. Moreover, Mephisto will torment Faustus with unspeakable pain while he is still alive. Ultimately, Mephisto effects Faustus by sending his demons to drag Faustus to his punishment.
CHORUS. Cut is the branch that might have grown full straight,
And burned is Apollo's laurel-bough,
That sometime grew within this learned man.
Faustus is gone: regard his hellish fall,
The character of Mephostophilis is a plot device used by Marlowe to advance our protagonists demise. From the outset, Mephostophilis is explicit in his intentions. He arrives not because he was summoned, but because he flew “in hope to get [Faustus’] glorious soul”. This is a stark rejection of Faustus’ anticipated dominance, and through sheer ignorance alone, Faustus fails to heed Mephostophilis warning that he is “a servant to great Lucifer and may not follow thee without his leave.” It can be argued that Mephostophilis words and actions have little impact on the plays arrogant, proud protagonist. Had Mephostophilis’ words “leave these frivolous demands” had an effect on Faustus’ character, then it is certain that he would not have died in such a brutal manner.
The idea established by some critics, that Mephostophilis has a ‘bewitching’ effect on Faustus suggests a level of duplicity; that Faustus does not understand the terms and conditions of the deal which he is entering. Yet the declarative “Faustus hath bequeath’d his soul to Lucifer” demonstrates the contrary. In the emotionally charged final scenes, Faustus exclaims “what hast thou done?” with the use of ‘thou’ incriminating himself, and himself alone, for his downfall. Fully aware that he will only have four and twenty years of frivolity, Faustus cannot claim that Mephostophilis is a ‘bewitching fiend’, for no ‘fiend’ would be so forthcoming with his intentions or loyalties.
Mephostophilis manipulates Faustus throughout, attempting to distract him from his inevitable end. He promises ‘fairest courtesans’ to Faustus and delights him with a parade of the Seven Deadly Sins when his resolve appears to waver and he considers the words of the good angel. Mephostophilis is evidently a lonely character, therefore uses his powers to ‘delight’ Faustus’ soul in order to satisfy his own desires of companionship.
Yet any relationship between Mephostophilis and Faustus is tainted by the expiry date; their friendship sours through the inevitability of its conclusion and indeed by the fact that Mephostophilis has been “servant to great Lucifer” all along.