Corporal is a low rank in Earth's forces below that of Sergeant. In the real world, "Corporal" is also used as a form of address for a Lance Corporal (a lower rank); while not referenced in dialog, animation cues may suggest that this lower rank also exists in the Earth forces. Ben Dixon, Henry Hurd, Johnson, Louis Nichols and Max Sterling are all addressed and/or referenced as "Corporal."

See Ranks (Earth) for a complete overview of Earth forces ranks.