Diana, I too have found it highly interesting that, at least on the Marteau/Grimaud version of this card, the Devil appears to be holding the blade of a sword. This is not, however, the case with most Marseilles versions. Even in the colouration of the Grimaud deck, one can recognise what appears to be flames (blue as the wings are) arising from the top of this instrument.
In other decks, it seems much more that it is a torch of some type which is held, and in the 1650 Noblet version (attached), a forked 'wand' or staff.
In each of these decks, it also seems that the pedastal upon which it stands is 'clearly' (at least to my eyes) an anvil. What is therefore also interesting is the consideration of the previous card's name with this aspect of the card, for to 'temper', in its full sense, one required an anvil. Yet this also lead to the craft very much 'stolen' (or divinely given) by the gods - Hephaestus, from whom Prometheus stole the Fire to give humanity (incidentally, some of you may by highly interested in obtaining a copy of Roger Sworder's Mining, metallurgy and the meaning of life, Quakers Hill Press, Sydney, 1995 - isbn 0 646 22836 6). In one aspect, both Hephaestus's anvil and the torched light are here represented.
Another aspect of the torch - as opposed to the lantern of VIIII the Hermit - is that underground chambers and caves were often investigated with such poor lighting instruments.
In the 18th book of Homer's Iliad, to return to the previous train of thought, it is mentioned that Haphaestus had maidservants who assisted him in his movements. It is worthy to note that, unlike the ambiguity (which I prefer) occuring in most Marseilles decks, the Noblet tied 'creatures' are clearly both female - in addition to one of the feet of the central figure appearing deformed, making it lame, as Hephaestus was!
With regards to the triple nipples, it was commonly believed that women who had an extra nipple (or two) were 'witches' (in the mediaeval church sense of this word) in league with the Devil. The additional nipple(s) there for suckling by the beast. When I first noticed it on the Conver deck I obtained a number of years ago, there was a moment of instant recognition that this was both appropriate and highly significant. It certainly indicates that those who are bound to the Devil's anvil are also feeding it.
But enough for now...
Attached, as mentioned above, is the (restored) 1650 Noblet version.