I tend to think that Odysseus' understanding of self regarding mortality is brought out in his discussion with Achilles. Throughout his journey in the underworld, Odysseus had been privy to many a story. All of them are connected through the thread that mortality had been extinguished. For Odysseus, his admiration of the power and awesome nature of Achilles, now a member of the underworld, triggers his own self- awareness about the nature of mortality. In a pointed exchange, the base for Odysseus' self- realization had become evident:
O shining Odysseus, never try to console me for dying.
I would rather follow the plow as thrall to another
man, one with no land allotted him and not much to live on, than be a king over all the perished dead.
For Achilles, life, even in the lowest of forms, is its own unique good. This is something that Odysseus begins to understand himself, a revelation that is completed when he quickly summons his men out of the underworld for fear of punishment or condemnation. The idea of being able to live life for what it is represents the epiphany concerning mortality that Odysseus gathers out his trip to the underworld. In Odysseus' understanding, life and the gift of mortality is something that cannot be squandered and the ability to return home to live it becomes a driving force, motivated by his epiphany.