When Odysseus returns home, he massacres the suitors trying to marry his wife in his absence. He sees the murder as the only possible way to regain control over Ithaka. The slaughter is justified by law and gods, with Athena joining the battle to support Odysseus.
Detailed answer:
Upon returning to Ithaka, Odysseus learns that a group of young men, “suitors,” have taken over his household. They have been trying to force Odysseus’ wife Penelope to marry one of them. Under the pretense of courting her, they occupied Odysseus’ house, wasting his wealth on feasts, wine, and entertainment. Odysseus returns home disguised as a beggar. With the support of Athena, his friends, and his son Telemachus, he kills all the suitors.
In Homer’s epic, the slaughter of suitors is depicted as a justified action. Odysseus elopes in a fit of rage upon knowing that his servants and fellowmen disrespected him, his wife, and his house. Odysseus feels that the people whom he has trusted betrayed him. He seeks revenge as the only possible way to restore order in his household. That way, he can reclaim his family and throne.
Before the slaughter, Odysseus gets approval from Athena. She assures him of victory and later joins the battle, and gets a sign of Zeus’s support as he prays to him. Homer depicts the slaughter as Odysseus’ blood sacrifice to gods. It is offered both in gratitude and compensation for his return and his wife and son’s safety and loyalty. The suitors personify lawlessness, savagery, and self-indulgence. Odysseus battles them to restore law and show his obedience to the gods.