There are no heroes in "Arms and the Boy." Ah, but there are heroic couplets. Unfortunately, there's nothing heroic about heroic couplets, so we're kind of back to square one on that front. But at least we know a little something about form.
Heroic couplets are rhyming couplets of iambic pentameter. That means that each line has five iambs all in a row, like line 11:
And God will grow no talons at his heels.
Here the daDUMs? Those are iambs, and when you've got five of 'em, you've got pentameter of the iambic sort. And since the lines come in rhyming pairs, well, there you have it: heroic couplets.
Why write in this form? Traditionally, it was reserved for epic poems about war and battles and all that typically heroic stuff. It could be that ol' Wilfred's making a deliberately ironic choice here, by using a heroic form to describe something that he thinks is not so heroic, even though everyone else seems to think it is. In fact, a whole lot of Owen's poetry comes to us in the form of heroic couplets, and a whole lot of his poetry is about the decidedly unheroic nature of war.
Sure, if we're looking at the big picture, "Arms and the Boy" is written in heroic couplets. But once you get down to the nitty gritty, once you go through those lines with a fine-toothed comb, you'll discover that it's actually pretty hard to scan. It's not all neat and pretty iambs with perfect end rhymes. Things are messy.
Many of the lines have extra syllables, or start off with trochees, or have an anapest thrown in (we're looking at you, line 1). And the last time we checked, "blade" and "blood" don't actually rhyme.
Why all the wonkiness? Well, we think that Owen's insistence on bucking up against the form and meter he's working in demonstrates the uneasiness we should feel about the subject matter of the poem. This isn't a neat and pretty little ditty about the glory of patriotic sacrifice. Instead, it's showing the seedy underbelly of war: the fact that it kills young boys for no real reason other than bloodlust. Or at least, according to Owen. His use of pararhymes (slant rhymes that share consonants), for example, gives us the illusion of a poem all tied up in a pretty formal bow, but immediately we're unsettled when our expectations of sound and sense are thrown right out the window.