|This article is about an older version of DF.|
The Fortress Guard is a military organization that essentially serves as a combined police and militia. Dwarves can be inducted into the Guard when the sheriff is promoted to the captain of the guard.
The game interface suggests 1/10 (rounded down) of the fortress population should be members of the fortress guard. Ignoring this requirement mostly just annoys nobles, and the captain of the guard will have to deal with justice matters on his own. Once the hammerer arrives, he will personally deal out his own brand of justice.
Guards act like military dwarves, but they cannot be commanded. They will attack any hostile creatures they see, but usually ignore wild animals. When not patrolling the fortress, they will engage in sparring or target practice the same way regular soldiers with the same assigned weapon will. In a siege, the fortress guard tend to make suicidal charges at the enemy and get slaughtered.
To assign a dwarf to the Fortress Guard, iew the dwarf, select references, and you will see a new option Fortress Guard. This option only appears after the Sheriff is promoted to Captain of the Guard.
Dwarves in the Fortress Guard spend most of their time sparring and will gain weapon (or wrestling) skill very quickly. Unfortunately, once they reach "Great" skill with their weapons, they will become heroes and can no longer be turned back into regular soldiers or civilians, greatly reducing their flexibility. If you want to retain use of dwarves in the Guard, either switch their weapons when they get above Adept, or rotate them into the regular military, where you can still give them orders. See Soldier#Heroes and Champions for more details.