In John Milton's Paradise Lost, how much does God's character deviate from his character in the biblical story? Can he be seen as a selfish dictator from an objective point of view (Satan sees him as such but is biased) or can he still be considered as a perfect, good, and just ruler?
Milton's Paradise Lost certainly focuses a great deal on Satan's perspective. In so much as the text reflects Satan's perspective, we can certainly see the text portraying God the Father as the selfish dictator Satan sees him to be. However, Milton also shows both sides of the story, especially when in Book III he takes his reader to Heaven. While God is certainly portrayed in Heaven as being in command, he is also portrayed as a just, merciful ruler, so in that sense Milton's God the Father does not deviate from the biblical God. It's only when God is discussed through the eyes of Satan that we see God as more of a tyrant.
Throughout any books that speak from Satan and his fallen angels' perspective, we see God portrayed as a tyrant. In Satan's view, there is no objective reason for God to be deemed sovereign ruler but rather only subjective reasons relative to God's own viewpoint. It's due to God's subjective sovereignty that Satan becomes jealous and decides to challenge God, leading to Satan's fall and eternal punishment in Hell. However, what's particularly interesting is that God chose to punish Satan simply because Satan's thinking did not align with God's own thinking, proving God to be, in Satan's eyes, a subjective tyrant. Satan expresses his view of the subjectiveness of God's decisions and God's tyranny in the first book when, complaining about their situation in Hell, Satan points out that the only reason why he is now in a place so different from Heaven is because God is the only one judging what is right and wrong. In using reason to judge God's own reason, Satan also compares himself with reason, even personifying reason and calling himself equal with reason. More specifically, Satan points out that God has deemed it right for Him to be as far removed from one who has become equal with reason, simply because God does not want anyone's reason to be considered more powerful than his own. We particularly see Satan describing God's tyrannical, subjective judgement and Satan equating himself with reason in Book I:
Is this ... the seat
That we must change for Heaven?--this mournful gloom
For that celestial light? Be it so, since he
Who now is sovereign can dispose and bid
What shall be right: farthest from him is best
Whom reason hath equalled [Satan], force hath made supreme
Above his equals.
In this passage, not only is Satan saying he is forced to be in Hell due to God's own subjective decision, he is also accusing God of using force to make Himself superior, which portrays God as a tyrant.
However, a legitimate question is, is Satan's perspective correct, because only if Satan is correct can we view Milton's God as being portrayed differently from the biblical God. We must remember that it was out of pride and jealousy that Satan decided to challenge God, and pride and jealousy are always inferior emotions. What's more, Milton gives us Book III to portray God's sense of justice. In Book III, God explains that since Satan and his fallen angels made their own choices to oppose God, they themselves alone are guilty, so they will be shown no mercy. On the other hand, Satan influenced Adam and Eve, so God rightly sees Satan as the more guilty party and justly decides that Adam and Eve should be pardoned. However, God also sees that true justice can't really exist unless Adam and Eve's sins are atoned for. If Adam and Eve don't atone for their own sins, then that means someone else has to. God is also portrayed as being just when he asks for someone to volunteer to accept Adam and Eve's punishment on their behalf, leaving the Son of God to volunteer. God is even further portrayed as just when he also states that Adam and Eve, and even Satan and his angels, were all given free will, so their falls are a direct consequence of their own choices and not something God ordained. All in all, in Book III, God is portrayed as being far more wise, noble minded, merciful, and even just than Satan sees Him as being and than Satan is himself.
Hence, while we can say that through Satan's perspective God is portrayed as being a tyrant, he is also shown to be a much more wise and just ruler than Satan sees Him to be and than Satan himself.