Master-at-Arms
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The non-commissioned responsible for internal security aboard Colonial warships, including battlestars. The Galactica's Master-at-Arms is Sergeant Hadrian.
Notes
Master-at-Arms (MAA) is a naval term relating to a Petty Officer aboard ship assigned to maintaining discipline.
Within the US Navy, larger vessels may have a number of MAAs, with the most senior being the Chief Master-at-Arms (CMAA), referred to as the "Sheriff".
Within the Royal Navy, the MAA is supported by a ship's Corporal-at-Arms.