He walks the halls of Apocrypha now. The power of the thu'um and the dragons, gone; the lost legacy of a long dead god, fallen into ashes like his shrines beneath the earth.
What is he, without that power? What is he now, but a hollow empty shell? His boundless confidence died with him before the Last, replaced by empty fury and the seeds of crippling self-doubt. He still has his ambition, even in this state, but there is nothing to aim for, and even bloodlust fails him. She has bested him, she has bested a god, and the disgust that writhes in this phantom gut equals the respect he now has for her.
Blood spilt; corpses fell in his wake, but the void still remains, and the glory he once knew as he raged across Solstheim is felt only in his dreams. He watches her fulfil the prophecies that were never truly meant for him, and he realizes his true role in this myth; that of bystander. An irrelevant footnote, a common obstacle, Alduin's lesser mirror at best, and now the tale is done.
A broken prototype, a living disappointment, and a forgotten legend. Was the choice ever his at all?