SATO Army

The SATO Army is a division of SATO responsible for ground engagements like the SATO Marine Corps. Unlike the Marine Corp, which is based off of warships, the Army is mostly garrisoned on planets and colonies. Their main area of operations would be the UNSA’s Capital world of Earth and other territories , but seeing Army troopers on naval ships to carry out military operations on far-flung colonies is not an uncommon sight. SATO Army troopers are among the surviving military forces aboard Retribution, along with the SATO Navy, Marine Corps, and Air Force.https://www.polygon.com/features/2016/11/2/13358380/call-of-duty-infinite-warfare-peter-w-singer-lost-touch-with-reality
One notable regiment during the Secession Wars was the 32nd Armored Regiment (Usef Omar's father was part of this regiment), which partook in the Battle of Deimos. 
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