Band
The trombonist was first, but he wouldn't be the last. As the story reset itself, trying in vain for a happier ending for the lovers, the next time Hermes woke at the bar there was a man playing an instrument for cash.
He played his trombone well, adding accompaniment to the story almost unnoticed by the others, and Hermes let him stay. By the next loop a cellist had joined, followed by a violinist. Next came a drummer, a bassist, a guitarist—his instrument not dissimilar from Orpheus's lyre—and finally a pianist.
Together their music provided a backdrop to Orpheus and Eurydice's story, and the crowds welcomed them as if they'd always been there. When Persephone came up top, they were there too, happily welcoming the spring goddess, and when she left their music was of utmost sorrow. But they played the most for Orpheus, Eurydice, and their love.
And whether the lovers succeeded or failed, the band would play on.