In dearth or in excessBoth the slave and the empressWill return to the dirt, I guessNaked as when they came
"In dearth or in excess" and "Both the slave and the empress" are merisms. A merism is a rhetorical device used to indicate a wide range by naming two opposites. The two here illustrate that, no matter his status or position, everyone dies.
"As naked as when they came" seems to be an allusion to Job 1:21: "And he [Job] said, 'Naked I came from my mother's womb, and naked shall I return. The LORD gave, and the LORD has taken away; blessed be the name of the LORD.'"
Near the end of the song, there's the line "Montezuma to Tripoli," which is also a merism.