Interpret: which character trait does Odysseus display in the land of the dead that he did not reveal earlier?
In the eleventh book of Homer's Odyssey, the title character travels to the land of the dead to consult with the spirit of the Theban prophet Teiresias. There are a number of things that happen in this book that might be candidates for things the audience has not encountered yet with respect to Odysseus.
For one, when Odysseus conjures up the spirits of the dead, he tells his Phaeacian listeners that "I turned pale with fear" (A.S. Kline translation). I don't recall Odysseus being fearful before this time.
Additionally, Odysseus encounters the spirit of his mother Anticleia. He did not know that she had died. Thus, it is not surprising that when he sees her he reacts as he does: "I wept at the sight of her, and my heart was filled with pity..." Later, after Odysseus does get a chance to talk to his mother, he tries to embrace her, but is unable and this made "the pain [seem] deeper in my heart." Of course, we see Odysseus weeping in Odyssey 5, but not due to grief at the loss of a dead family member.
Near the end of Odyssey 11, we also see Odysseus trying to soothe the spirit of Ajax, who was still angry with Odysseus over their contest over the armor of Achilles. It seems to me that this may be the first time we have seen this side of Odysseus.