Pity the poor peon. He exists at the very bottom of the food chain of servitude, beneath wage-slaves, underlings, drudges, or even minions. His boss doesn't even know he exists.
Peon was a Mexican word originally, meaning an agricultural worker in servitude to his landlord. Today, peon has a more comic ring to it and is usually used in fun — though if you are a personal assistant to a tyrannical Hollywood star, for example, it's probably no laughing matter.