Oh, Thank the Gods

The gods in the Iliad take an active role in the lives of mortals and attempt to control their fate. The gods play a large role in the Iliad, including playing a role in starting the Trojan War. Zeus knew the prophecy that the son of Thetis, a sea nymph, would be greater than the father. In a precaution, Zeus married Thetis to a mortal, Peleus, to be sure that the son would cause no problems for Zeus. The wedding between Thetis and Peleus was a catalyst to the Trojan War because Eres caused the competition between Aphrodite, Hera, and Athena for the fairest goddess, which lead to Paris having to choose who he believes to be the fairest and winning Helen in the process. Helen's abduction started the war and the gods watched every minute of it from the sidelines, sometimes even fighting in the war itself. The gods choose sides during the war and attempt to even the odds in their favor during the war.
The gods take a part in the mortal world sometimes by taking the form of mortals and trying to turn the war in their favor, such as when Apollo speaks into Hector's ear and persuades him towards a particular course of action or filling him with strength during battle. The role of the gods can seem metaphorical, explaining the changes of moods or their ferocity on the battlefield, however the gods also can act directly during the war. The gods can take part in the battle, such as when Diomedes fights Aphrodite or when Achilles is held back by Athena. The Greeks insult Apollo in the beginning of the Iliad, which brings a plague upon the Greeks until they can please Apollo. Sometimes the gods can even preform miraculous actions, such as Aphrodite rescuing Paris from his duel with Menelaus or Hephaestus forging the new extraordinary armor for Achilles. The battle between Troy and the Greeks can also be seen as a battle between the gods. Zeus tries to preside over the conflict, while Hera, Athena, and Poseidon support the Greeks and Aphrodite, Ares, and Apollo assist the Trojans. Although the gods are passionate about the fate of the war, they don't quite  feel the agony of mortal men who must die. The gods relate to humans, some even have mortal children, but they can never understand the passion mortals feel during their lives because it is just a blimp to the gods.