Please help!!

Carefully read this stanza from Stephen Crane's poem War Is Kind, and answer the question that follows:

Hoarse, booming drums of the regiment,
Little souls who thirst for fight,
These men were born to drill and die.
The unexplained glory flies above them.
Great is the battle-god, great, and his kingdom
A field where a thousand corpses lie.

Please discuss how the author uses irony in this excerpt.