Well, they were both new creations essentially left alone in a world they knew nothing about. Both had responses that went arwy and cause many to suffer. Both of them did not intend for the consequences of their actions to be so drastic; they just did not fully comprehend because they had no one to show them the correct way to behave.
Is he? Lucifer tells that he is superior to humans for he's made of fire,but he still address god as his lord.
No. The tragic hero of this epic poem is actually Satan.
The poem is written about humanity's fall from Paradise and heavily focuses on Satan's role. In the poem we learn about Satan's fall, his "inner" reasoning, and his desire for power. Because the poem is centered around him, he is Aristotle's' nontraditional "tragic hero."
He suffers a fall from high power (he loses his own paradise- Heaven), tries to redeem power (tempting man), and at the end of the story seems to accept his lowly fate (as a snake in Hell).
One of the reasons Satan is projected as the hero is because people can better relate to a sinful character instead of virtuous characters like the Son or God.
Although Adam loses his paradise too, his loss isn't as impressive as losing Heaven.
Also Adam is quickly redeemed and finds forgiveness from God quickly. There also wasn't as much poem devoted to developing the character of Adam, as there was Satan.
However, in an essay, I bet you could argue either Satan or Adam as a tragic hero with enough evidence from the text.