There was one who took the alternate role for the serpent, aside from the famous Lucifer. His name was
Samael.
It is said that on the sixth day, God was so pleased with Adam he wanted the angels to bow down to him. Samael refused, and Michael warned him of the consequence of his disobedience. But Samael gathered many angels of like mind to him and said something to the effect of “Let God try!” and Michael promptly tossed him out of heaven.
Now, at the risk of being accused of crossing the allegory line, I’d say we see hints of Saruman here. He didn't think Men were good enough to rule Middle-earth—which was Ilúvatar's plan. In this case, however, his downfall was brought about by the very beings he thought weren’t good enough.