What is ironic about the character of teiresias?
Ah, the age-old question!
How can a blind old man know the truth better than a young king with perfect vision? How can someone who looks like a beggar be a better advisor to the king than his own two eyes? How can someone so humble, a self-deprecator, tell the King that he should not pursue the truth? How dare he!
Did Teiresias solve the Riddle of the Sphinx? Did he become King? Did he save the city from death, destruction, and plague? No, no, and no!
Why then does Teiresias have the audacity to say...?
Aye, for ye all are witless, but my voice
Will ne'er reveal my miseries—or thine.
I say thou art the murderer of the man
Whose murderer thou pursuest.
Poor fool to utter gibes at me which all
Here present will cast back on thee ere long.
To twit me with my blindness—thou hast eyes,
Yet see'st not in what misery thou art fallen,
Nor where thou dwellest nor with whom for mate.
The answers are, of course: irony, irony, and irony.