Goblin Peons are the most basic melee units of the Goblin Army. They follow Fighter AI. Approximately one out of every five goblins will be a Peon (17.8% chance to spawn). They are able to break down Doors that are in their way (Doors then drop as collectible items).
Goblin Peons are only two Blocks tall (instead of the 3 block player height) and can fit through smaller gaps in the player's walls.
The Bestiary entry for the Goblin Peon: "Common footsoldiers of the Goblin Army, these foul creatures are good for little more than cannon fodder... and breaking down doors."