Something that really struck me in Book X was Milton going out of his way to explain that the serpent is innocent:
Are to behold the Judgement, but the judg’d,
Those two; the third best absent is condemn’d,
Convict by flight, and Rebel to all Law
Conviction to the Serpent none belongs (81-84).
It seems pretty obvious that the physical serpent played no role in the temptation of Eve but that it was Satan who possessed him who takes the blame. However, I’m wondering if/how this speaks into the common interpretation of Judas the Iscariot and his betrayal of Jesus. The gospels say that “Satan entered into him” (John 13:27) much like we see Satan entering the serpent in Paradise Lost, but we see Judas feel terrible about what he has done and eventually commit suicide from the agony. It is commonly accepted that while Satan was guiding Judas to sell Jesus off to the Romans for His crucifixion, he is ultimately responsible for the decision and will be judged accordingly.
This now goes into the territory of free will vs. predestination, but what I’m really asking is what warrants judgement; is it because the serpent is an animal that it has no control or responsibility as opposed to Judas who is a rational being with a soul? It makes sense, but just how much Judas was able to resist Satan despite the possession is something I’ve always wondered.