War is full of death, and "Arms and the Boy" has plenty of the Big D in it. The boy's bayonet-blade resembles some kind of murderous monster (it is hungry for "flesh"), his bullets want to bury themselves in the chest of an enemy, and his cartridge is compared to a mouth of sharp, canine teeth. As if this weren't enough, the entire last stanza talks about various killing instruments—claws, talons, and antlers. So by the end of the poem, we're left with one big question: when will it ever stop?
War kills people in many different ways; the boy is "alive," but the speaker and others like him want to turn him into a lifeless, killing machine.
Even though war turns people into killing machines, this change is never permanent. The final stanza says that the boy will never acquire talons and claws, which suggests that he will never become a full-fledged cold-blooded killer.