The 13th Autonomous Corps was a Mobile Suit unit, comprising of GAT-01 Strike Daggers, of the Earth Alliance Forces, during the First Alliance-PLANT War. It went into action during the Battle of Panama, and was close in successfully defending the spaceport, only for ZAFT's Gungir EMP weapons effectively disabling their mobile suits, due to them not having proper EMP shielding. The corps, along with the entire garrison of Porta Panama was then summarily massacred by vengeful ZAFT soldiers.
Battle of Porta PanamaThe 13th Autonomous participated in the Battle of Porta Panama, when ZAFT attacked the Mass Driver, and the base commander ordered them deployed into the battle. The initial attack by the corps caught the ZAFT Forces off guard, as the GAT-01 Strike Daggers dealt heavy casualties onto the ZAFT GINNs. Unfortunately, ZAFT dropped it's Gungir EMP weapons onto specific drop points where the major fighting was taking place. The resulting blast sent an EMP wave which disabled all Earth Alliance equipment, including the Strike Daggers of the 13th, due to the mobile suits not having any proper EMP shielding.
Trapped in their disabled mobile suits, the pilots of the 13th Autonomous Corps were sitting ducks for blood drunk ZAFT forces, who wanted revenge for the disaster of Operation: Spitbreak.
The lessons learned from the battle showed the Earth Alliance the need to have proper EMP shielding to Mobile Suits, which they did. And after Panama, the Strike Dagger, along with it's more advanced cousin unit, the GAT-01A1 Dagger, performed much better on the field.