The Iliad may be seen as an account of the circumstances that irrevocably alter the life of one man: Achilles, one of the greatest warriors. Throughout the course of the poem Achilles goes through many ordeals that change his character immensely. Starting with his quarrel with Agamemnon and withdrawal from battle, to the death of Patroklos, and with the slaying of Hektor. Achilles emotions and actions decide the fate of many warriors on both sides. Achilles struggles with anger, honor, pride, loyalty and love make the poem more that just a gruesome war story.
A large source of Achilles anger started with his fight with Agamemnon. Apollo put a plague on the Achaean soldiers that was killing them off. The only way to stop this from killing them all was to give back a priests daughter who had been captured. This girl belonged to Agamemnon and he didnt want to give her up unless he got Achilles girl in return. This would disgrace Achilles honor but he could not let any more soldiers be killed so, he reluctantly let her go. But in return for giving up his girl he withdrew from the battle. Much of Achilles anger is a result of this occasion but the death of Patroklos later overrode his previous anger to Agamemnon.
The death of Patroklos touched Achilles in many ways that changed and shaped his character. Many emotions were a result of his death such as love, loss, anger, and sadness. Patroklos was a dear friend to Achilles and when a mix of divine intervention and Hektor cut Patroklos down grief and the desire to avenge his dear friends death consumed Achilles. This switched his anger from King Agamemnon to Hektor, the man who slew his dear friend. This anger drew Achilles to avenge the death of his friend, to kill Hektor.
The slaughter of Hektor is gruesome and horrid. Not only did Achilles kill Hektor but, he hung him by his ankles, attached him to his chariot and dragged Hector around the burial site of Patroklos. This is horrible enough but Achilles for a while refused to give Priam, father of Hektor and King of Troy, back the body of Hektor for proper burial. He was going to let it be eaten by the dogs, though the gods protected his body from this.
This shows Achilles anger and how brutal he seems. But when Priam comes to retrieve the body of Hektor, Achilles welcomes him like a friend and calls for a cease-fire so that Hektor can be properly buried. Achilles drive for blood and vengeance is gone. He mourns with Priam, which illustrates that Achilles may be harsh but he can also be kind and caring. This may also be a sign that Achilles is maturing as a person and growing up. Throughout the poem Achilles seems like a horrible wretched person though in the last book he shows signs of maturity.
Achilles is a man of noble principles all throughout the poem. His argument with Agamemnon is a testament to that. Achilles shows that his principles rank higher than desire for fame on the battlefield. The only point at which he compromises his principles is when he allows Patroklos and his men to go off and fight and refuses to go himself. At that point in the story, he is putting foolish pride before his loyalty and love for his friend. This is the tragedy of human flaws that goes along with anger. He chooses a fate of death over dishonor, truly a heros decision. Then after he avenges his fallen companion and the blood lust has left his system, he shows his growth and new understanding of loss with Priam. It is not an all-new Achilles, but instead the same Achilles who is perhaps wiser due to the lessons that only death can teach.