The poem "Song of Elli" from Peter S. Beagle's "The Last Unicorn" reflects on the themes of loss and the nature of existence. It expresses the idea that while some things can be restored or continue to exist in different forms, loss is a profound and defining experience. The lines emphasize the inevitability of change and the transient nature of life, suggesting that what is lost becomes permanent, and the pain of that loss can linger.

The poem also touches on the concept of choices, highlighting that those without options must accept their fate and learn to love what they have even as they struggle with what they have lost. The interplay between what is real and what can be undone underscores life's complexities, capturing a sense of resignation to the nature of existence while acknowledging the deep emotional connections formed through love and loss.