Mephistopheles on stage

Devil - an evil spirit (with Cap) the supreme spirit of evil
The chambers dictionary's defenition of Mephistopheles' manifestation, I would argue, is not an accurate assumption of the character. The term is too broad, and I would argue that the word 'evil' could be applied no more to Mephistopheles than to Dr. Faustus. This leads us to the question: how should an actor go about playing the role of mephistopheles on-stage?
When mephistopheles fist appears to faustus in the form of a friar, he states that, 'when we hear one rack the name of God...we fly in hope to get his glorious soul, nor will we come unless he use such means whereby he is in danger to be damned.'
This can be interpreted as mephistopheles revealing something of his true nature to Faustus, stating that he searches for vulnerable souls, ripe for damning, as this is either his duty to his master Lucifer, something he takes pleasure in, or perhaps both. Alternatively, it could be mephistopheles warning Faustus that he is in danger of loosing his soul, by so willingly playing around with the dark arts, and that he should meaningfuly repent to 'his Saviour Christ' immediately.
Going on the conventional defenition of 'Devil', derrived from biblical accounts of devils, an actor would most probably be more inclined to be the more menacing interpretation at this point. However, in Act 2 Scene 1, it seems that Mephistopheles regularly drops hints to Faustus that he can reafirm his soul as his own at any time. E.g. 'that security craves great Lucifer. If thou deny it, I will back to hell', and 'But tell me, Faustus, shall I have thy soul?' Mephistopheles even seems ashamed later in this scene, saying to himself Aside, 'O, what will I not do to obtain his soul?...I'll fetch him somewhat to delight his mind.' At first, I enterprated this as the typical 'oh, what have i done/become' speach, but when analysed further, I saw that the lines could be chuckled, as if manically laughing to himself, asking the rhetorical question of 'What will I not do to obtain his soul? nothing! I am a devil after all.'
When Faustus begins to waver on his contract, Mephistopheles says to him, 'Why Faustus, think'st thou heaven is such a glorious thing?...tis not half so fair as thou'. It would be difficult to pay a reluctant devil for this line, as sarcasm or difference of context could not be applied to the constant of Heaven. It seems much more viable that the Mephistopheles who says this line is attempting to trick Faustus, and stop him from ripping up his contract by repenting. Furthermore, when Faustus says to him, 'Go, accursed spirit, to ugly hell! tis' thou hast damned sistresses Faustus' soul', Mephistopheles does not feel guilt, or permit faustus to repent whilst he returns to hell peacefully; rather he goes and fetches the king of devils (chambers dictionary's '(Caps) Devil' - the supreme spirit of evil), who bullies Faustus into remeaining true to his contract.
Mephistophiles can be seen to discourage Faustus to enjoy rome, and rather encourages faustus in mischief. 'Now', says mephistopheles, placing a cloak of invisibility on Faustus, 'do what thou wilt'. Surely, a more reserved character would permit Faustus to enjoy his 24 years respectfully, and discourage further sin. So we find a more steriotypical devilish (in terms of mischievous) side of mephistopheles here. Mephistopheles even pokes fun at the church with Faustus, sarcasticly saying 'We shall be cursed with bell, book, and candle', which only encourages his mortal master in his sin, as they beat the friars together.
But, mephistopheles' comparitively quieter character, who appears during faustus' performances, can be interpreted as the middleman who has just given up with trying to convince Faustus to rip up his contract. Hardly saying a word, he simply does as Faustus commands. But when he sees a new opportunity to preserve innocence, the Horse Courier that is an 'honest fellow, and he has a great charge, neither wife or child.' the critic J D Jump states that 'a horse-dealer had a ready-made reputation for dishonesty', so the audience would want to see him cheated. Here, Mephistopheles is presented as more moral than Faustus and indeed the audience, as he is the only one who wishes goodwill on someone. However, this is not the same for the Old Man in Act 5 Scene 3, the holiest and therefore most morally acceptable person in this play. Mephistopheles tries to tempt the man into sin, which he has not done to anyone so far in the play; 'I cannot touch his soul. What I may afflict his body with I will attempt, which is but little worth.'
To conclude, the last line of the play, 'Ah, Mephestopheles' as said by faustus, could be a scream of betrayal, or perhaps a cry for his last friend to help him out of hell. The entire character of mephistopheles can be summarised in a very simmilar way; Either the actor plays him as a typical devious devil, or as one who wishes for none to share the same fate as him. Perhaps mephistopheles only holds his end of  the bargin with faustus, because he is just as scared of lucifer as faustus is. Or perhaps he secretly enjoys damning souls; as he says in the play, 'Solamen miseris socios habusisse doloris' - it is comfort to the wretched to have companions in misery.